TW201830811A - Structure of vcsel and method for manufacturing the same - Google Patents

Abstract

The invention refers to a Vertical-Cavity Surface-Emitting Laser (VCSEL) having a novel three-trenches structure. By forming a first trench within a mesa around the periphery of an output window of the VCSEL, the overall capacitance is decreased and the time used in the oxidation process for an oxidation layer is shortened. By forming a second trench and a third trench on the periphery of the mesa in a step-like concave manner, the mesa becomes a step-like structure having double mesa-layers. Such that, a larger heat-radiating area can be obtained for decreasing thermal effects, while the metal-gap defects of the metal layer can also be avoided. An implant layer is formed around the periphery of the output window for controlling the modal and constraining the currents, in addition, an output layer is formed on the output window for controlling the output light.

Description

 Vertical cavity surface-emitting laser structure and method  

The invention relates to a vertical resonant cavity surface-emitting laser structure and a manufacturing method thereof, in particular to a vertical resonant cavity surface-emitting laser structure and a manufacturing method for reducing the overall capacitance and shortening the oxidation process time by the three-ditch structure.

Vertical Cavity Surface Emitting Laser (VCSEL) is one of the luminescent laser diodes. Due to its low power and low price, it is mainly used in regional networks and has "high speed". The advantage with "low price". The raw materials for VCSEL luminescence and photodetection are generally gallium arsenide (GaAs) and indium phosphide (InP), and the epitaxial wafer is usually prepared by organic metal vapor deposition (MOCVD). Compared with the general side-projection type laser, the mirror surface required for the resonant cavity of the VCSEL and the photon to resonate back and forth in the resonant cavity is not formed by the natural lattice fracture surface formed by the process, but is formed when the element structure is epitaxially grown.

A general VCSEL structure generally includes a luminescent active layer, a resonant cavity, and a Bragg reflector (DBR) having a high reflectivity on the upper and lower sides. When the photon is generated in the luminescent active layer, it is easy to oscillate back and forth in the resonant cavity. If the population is in the population inversion, the laser light is formed on the surface of the VCSEL element. The VCSEL adopts a surface-emitting type, and the laser light has a conical shape, which is easier to couple with the optical fiber, and does not require an additional optical lens. For the basic structure, process and operation of the conventional VCSEL, reference is made to the contents of US Pat. No. 4,949,350 and US Pat. No. 5,468,656.

The invention improves the structure and the manufacturing method of the above-mentioned conventional VCSEL, and reduces the overall capacitance and shortens the oxidation process time by the unique three-ditch structure, and controls the modal state and the limited current by the ion implantation area around the light window. And a light layer is formed on the light window to control the light, and the heat conduction is reduced by the stepped double-layered pillar structure to reduce the thermal effect.

In view of the above, the main object of the present invention is to provide a vertical cavity surface-emitting laser structure and a manufacturing method thereof, which can reduce the overall capacitance, shorten the oxidation process time, and form a stepped double-layer boss by a unique three-ditch structure. Structure to reduce thermal effects.

Another object of the present invention is to provide a vertical cavity surface-emitting laser structure and a method for controlling a mode and a current by an ion implantation area around a light window, and forming a light layer on the light window to control The light-emitting layer may be a dielectric material, and the material composition may be cerium oxide (SiO2), tantalum nitride (SiN) or a mixture of the two materials, and the reflection coefficient is between 1.5 and 2.0.

To achieve the above objective, the present invention provides a vertical cavity surface-emitting laser structure comprising: a substrate, a first mirror layer on the substrate, an active layer on the first mirror layer, and a second The mirror layer is disposed on the active layer, the oxide layer is disposed in the second mirror layer, a land region, a first trench, a second trench, a third trench, a dielectric material, and a first contact layer And a second contact layer; wherein the land region is above the substrate and is composed of at least a portion of the first mirror layer, the active layer, the second mirror layer, and the oxide layer Forming a light window at a center of a top surface of the land area; the first trench is at least a portion of the outer circumference of the light window and surrounding the outer periphery of the light window; a trench is formed by the top surface of the land region extending at least from the top to the second mirror layer, the oxide layer and the active layer; the second trench is at least one portion surrounding the outer periphery of the land region And spaced apart from the first trench, the second trench is at least from top to bottom The second mirror layer and the oxide layer are such that a bottom of the second trench is located at the active layer or at the first mirror layer; the third trench is surrounded by the periphery of the land region At least a portion of the edge is recessed downward from the bottom of the second trench, and the third trench extends through the first mirror layer from top to bottom such that a bottom of the third trench is located at the base The dielectric material is at least filled in the first trench; the first contact layer is on the top surface of the land region and is in contact with the second mirror layer; the second contact layer is located at least The bottom of the third trench and at least in contact with the substrate.

In a preferred embodiment, the vertical cavity surface-emitting laser structure further includes an insulating layer covering at least a portion of an outer surface of the land region, and the first contact layer and the second contact At least a portion of the layer is exposed to the insulating layer; the first mirror layer is an n-type distributed Bragg reflector (DBR), and the second mirror layer is a p-type distributed a Bragg mirror layer; the material of the first mirror layer and the second mirror layer comprises aluminum gallium arsenide (AlGaAs) having a different percentage of aluminum moles, and the oxide layer has a relatively highest Mo in the second mirror layer The percentage of aluminum in the ear; the oxide layer extends horizontally from the inner periphery of the first trench toward the center of the land region; the dielectric material is a low dielectric property polymer material; and the first contact layer and the The second contact layer is a metal layer.

In a preferred embodiment, the vertical cavity surface-emitting laser structure further includes an ion implantation layer located in the second mirror layer. The ion implantation layer overlaps with the oxide layer, and the optical mode is controlled by the relative pore size of the oxide layer and the ion implantation, wherein the ion implantation belongs to a Gain-guided, and the oxidation belongs to an index guided The optical mode is controlled by a hybrid application of the two; and the ion implant layer located in the land area is located between the light window and the first trench and surrounds the light window At least a portion of the outer periphery; wherein the first contact layer is in contact with an upper surface of the second mirror layer.

In a preferred embodiment, the vertical cavity surface incident laser structure further includes: a light exiting layer on the light window of the top surface of the land area.

In a preferred embodiment, the second contact layer extends from the bottom of the third trench along one of the third trench and the second trench to each of the second mirror layer. a top surface, wherein a top surface of the second contact layer is substantially at the same height as the first contact layer; a bottom surface of the second trench forms a plane, and the second contact layer is in the second trench The bottom portion constitutes a horizontally extended state.

To achieve the above object, the present invention provides a method of fabricating a vertical cavity surface-emitting laser structure, comprising the steps of: providing a laser wafer substrate on which a semiconductor process is performed from bottom to top by a semiconductor process Forming sequentially: a substrate, a first mirror layer on the substrate, an active layer on the first mirror layer, and a second mirror layer on the active layer; using a first mask and implementing a first a mask process, forming a first mask layer having a first predetermined pattern on the upper surface of the second mirror layer, the first predetermined pattern being a pattern corresponding to the first mask; performing an ion implantation a process of ion-implanting a region of the second mirror layer that is not covered by the first mask layer to form an ion implant layer, and a bottom portion of the ion implant layer is still at a predetermined height from the active layer; Forming a second mask and performing a second mask process on the upper surface of the second mirror layer and the first photoresist layer without removing the first mask layer a second mask layer having a second predetermined pattern, the The second predetermined pattern is a pattern corresponding to the second reticle; performing a first etching process to perform the second mirror layer, the active layer, and the region where the first mirror layer is not covered by the second photoresist layer Etching to form a first trench, and the first trench extends downward from the upper surface of the second mirror layer to the second mirror layer and the active layer such that a bottom portion of the first trench is located at the first a mirror layer; an oxidation process is performed to form a horizontally extending oxide layer in the second mirror layer through the first trench, and the oxide layer is close in height to the ion implant layer, even a portion is overlapped; a second etching process is performed to form a second trench on the second mirror layer, and the second trench is at least penetrating the second mirror from the upper surface of the second mirror layer a layer and the oxide layer such that a bottom of the second trench is located at the active layer or at the first mirror layer; a third etching process is performed to be at the bottom of the second trench Forming a third ditches that are recessed downward, and the third ditches are upwardly At least a bottom portion of the third trench is located at the substrate; the first trench is filled with a dielectric material, the dielectric material is a polymer, which is a Polymide, and has a reflection coefficient of 1.5. ~1.6. By digging out the first trench and filling the polymer, the area of the semiconductor material having a high dielectric constant can be reduced, so that the capacitance can be reduced. And forming an insulating layer, a first contact layer and a second contact layer respectively in the appropriate regions on the laser wafer substrate; wherein the first contact layer is located on the top surface of the land region and is in contact with On the upper surface of the second mirror layer; the second contact layer is located at least at the bottom of the third trench and at least in contact with the substrate, and the second contact layer is along the bottom of the third trench Each of the third trench and the second trench respectively has an inclined surface extending upward to an upper surface of the second mirror layer such that a top surface of the second contact layer is substantially at the same height as the first contact layer At least a portion of the first contact layer and the second contact layer are exposed to the outside of the insulating layer; wherein the second trench and the third trench define a convex on the laser wafer substrate a second region, the second trench and the third trench are both at least a portion of an outer circumference surrounding the land region; the land region is above the substrate and is at least a portion of the a mirror layer, the active layer, the second mirror layer, and the The oxide layer is configured to have a light window at a center of a top surface of the land area; the first trench is located in the land area and surrounds at least an outer circumference of the light window A portion is spaced apart from the second trench; the first trench is formed by the top surface of the land region extending from the top to the bottom through the second mirror layer, the oxide layer and the active layer.

The detailed description of the present invention and the accompanying drawings are to be understood by the claims .

10‧‧‧Base

21‧‧‧ first mirror

22‧‧‧Active layer

23‧‧‧Second mirror

231‧‧‧Oxide layer

24‧‧‧Ion implant layer

240‧‧‧ upper surface

25‧‧‧Insulation

26‧‧‧Dielectric materials

27‧‧‧metal layer

270‧‧‧ first contact layer

271~273‧‧‧Second contact layer

2710‧‧‧ top surface

274‧‧‧Lighting layer

30‧‧‧Boss area

300‧‧‧light window

31‧‧‧First ditches

32‧‧‧Second ditches

321, 331‧‧‧ bottom

33‧‧‧ Third Ditch

51, 52‧‧‧ patterns

510, 520‧‧‧ center circle area

511‧‧‧ring area

521‧‧‧ peripheral area

5100, 5110, 5200, 5210‧‧‧ mask

1 is a schematic cross-sectional view of a vertical resonant cavity surface-emitting laser structure according to a preferred embodiment of the present invention; and FIG. 2A is a first stage schematic diagram of a vertical resonant cavity surface-emitting laser structure of the present invention; FIG. A schematic diagram of an embodiment of the pattern of the first photomask of the present invention; FIG. 3A is a schematic diagram of a second stage of the method for fabricating a vertical cavity surface-emitting laser structure of the present invention; FIG. Schematic diagram of an embodiment of a pattern of a reticle; FIG. 4 is a third stage diagram of a method for fabricating a vertical cavity surface-emitting laser structure of the present invention; FIG. 5 is a method for fabricating a vertical cavity surface-emitting laser structure of the present invention. The fourth stage schematic diagram; FIG. 6 is a fifth stage diagram of the method for fabricating the vertical cavity surface-emitting laser structure of the present invention; and FIG. 7 is the sixth stage of the method for fabricating the vertical cavity surface-emitting laser structure of the present invention. schematic diagram.

The vertical cavity surface-emitting laser structure and method of the invention mainly reduces the overall capacitance, shortens the oxidation process time, and forms a stepped double-layered pillar structure to reduce the thermal effect by a unique three-ditch structure. Moreover, the modality and the localized current are controlled by the ion implantation area around the light window, and an outgoing light layer is formed on the light window to control the light output.

Please refer to FIG. 1 , which is a cross-sectional view of a vertical resonant cavity surface-emitting laser structure according to a preferred embodiment of the present invention.

In the present embodiment, the vertical cavity surface-emitting laser structure of the present invention is constructed on a laser wafer substrate mainly composed of gallium arsenide (GaAs) or indium phosphide (InP) materials. And the substrate is sequentially included from bottom to top: a substrate 10, a first mirror layer 21 is disposed on the substrate 10, an active layer 22 (Active Region) is located on the first mirror layer 21, and a second The mirror layer 23 is located on the active layer 22. An oxide layer 231 (Oxide Layer) is interposed in the second mirror layer 23. In this embodiment, the first mirror layer 21 is an n-type distributed Bragg reflector (DBR), which may also be referred to as a lower mirror layer, and the second mirror layer 23 is a p-type. The distributed Bragg mirror layer can also be referred to as the upper mirror layer. The material of the first mirror layer 21 and the second mirror layer 23 comprises a multilayer structure of aluminum gallium arsenide (AlGaAs) having a different percentage of aluminum moles, and the oxide layer 231 has a relative orientation in the second mirror layer 23. The highest percentage of moles of aluminum. Thereby, the oxide layer 231 can form insulating alumina (Al 2 O 3 ) during the oxidation process during the oxidation process.

The vertical cavity surface-emitting laser structure of the present invention further comprises: a land area 30 (Mesa), a first channel 31 (Isolation Trench), a second channel 32, and a third channel 33. , a dielectric material 26 (Dielectric Material), a first contact layer 270 (Contact Layer), a second contact layer 271 ~ 273, an ion implant layer 24 (Implant Region), an insulating layer 25 (Insolating Layer) And a light output layer 274 (Power Output Layer).

The land region 30 is formed on the substrate 10 and is composed of at least a portion of the first mirror layer 21, the active layer 22, the second mirror layer 23, and the oxide layer 231. There is a light window 300 at a center of a top surface of the land area 30. In the present embodiment, the oxide layer 231 is close to the bottom of the ion implantation layer 24 in height, and even some overlap.

The first trench 31 is at least partially located within the land region 30 and surrounding the outer periphery of the light window 300. The first trench 31 is formed by the top surface of the land region 30 extending from the top to the bottom of the second mirror layer 23, the oxide layer 231 and the active layer 22, so that the bottom of the first trench 31 is located at the first Mirror layer 21.

The second trench 32 is at least a portion of the outer circumference surrounding the upper half of the boss region 30 and spaced apart from the first trench 31 by a distance. The second trench 32 extends through the second mirror layer 23 and the oxide layer 231 from top to bottom such that a bottom portion 321 of the second trench 32 is located at the active layer 22 or at the first mirror layer 21 One of them. The oxide layer 231 extends horizontally from the inner periphery of the trench 31 toward the center of the land region 30.

The third trench 33 is at least a portion of the outer circumference surrounding the lower half of the land region 30 and is recessed downward from the bottom portion 321 of the second trench 32. The third trench 33 extends from the top to the bottom of the first mirror layer 21 (or through the active layer 22 and the first mirror layer 21) such that a bottom portion 331 of the third trench 33 is located therein. At the upper surface of the substrate 10.

In the present embodiment, the dielectric material 26 is preferably a low dielectric material polymer material, and the dielectric material 26 is at least filled in the first trench 31 to provide a reduced vertical cavity surface area. The effectiveness of the overall capacitance of the structure. In this embodiment, the dielectric material 26 is a polymer, which may be Polymide, and has a reflection coefficient of 1.5 to 1.6. In the present invention, by excavating the first trench 31 and filling the polymer (dielectric material 26), the area of the semiconductor material having a high dielectric constant can be reduced, so that the capacitance can be reduced. The first contact layer 270 and the second contact layer 271-273 are both part of the metal layer 27. The first contact layer 270 is an upper surface 240 on the top surface of the land region 30 and in contact with the second mirror layer 23. The second contact layer 271, 272, 273 is located at least at the bottom 331 of the third trench 33 and at least contacts the substrate 10. In this embodiment, the second contact layer 271, 272, 273 extends from the bottom portion 331 of the third trench 33 along the third trench 33 and the second trench 32 to an inclined surface. The top surface 240 of the second mirror layer 23 is such that a top surface 2710 of the second contact layer 271, 272, 273 is substantially at the same height as the top surface of the first contact layer 270. Therefore, the first contact layer 270 and the second contact layer 271, 272, 273 of the present invention are not only located on the same side of the substrate 10, but also at substantially the same height position, which facilitates the subsequent wire bonding process. In addition, a plane is formed on the bottom portion 321 of the second trench 32, so that the second contact layer 271, 272, 273 forms a horizontally extending state at the bottom portion 321 of the second trench 32. Thereby, not only a stepped double-layered boss structure can be formed, but a larger lower-layer boss can increase the heat-dissipating area and reduce the thermal effect, and at the same time, the inclined surfaces of the second and third trench structures 32, 33 of the two-stage recessed The slope is slowed and a flat surface is formed in the bottom portion 321 of the second trench 32, so that the second contact layers 271, 272, and 273 are less likely to cause gold breakage when plating, sputtering, or vapor deposition of the metal layer.

The ion implant layer 24 is located in the second mirror layer 23 and above the active layer 22. In the present embodiment, the bottom portion of the ion implantation layer 24 partially overlaps the oxide layer 231, and the optical mode is controlled by the relative aperture size of the oxide layer 231 and the ion implantation 24. Among them, ion implantation belongs to Gain-guided, and oxidation belongs to index guided. The optical mode can be controlled by the mixed application of the two. Moreover, the ion implantation layer 24 located in the land region 30 is at least a portion between the light window 300 and the first trench 31 and surrounding the outer periphery of the light window 300. The first contact layer 270 is in contact with an upper surface of the ion implantation layer 24. The present invention can be used to control optical modes and localized currents by using an ion implantation area 24 additionally disposed around the light window 300. In this embodiment, the ion implantation process can implant protons or oxygen ions, depth. Between 2~4um.

The insulating layer 25 covers at least a portion of an outer surface of the land region 30, and at least a portion of the first contact layer 270 and the second contact layer 271, 272, 273 are exposed to the insulating layer. 25 outside. The light exit layer 274 is located on the light window 300 of the top surface of the land area 30 and can be used to control the light output. The principle is to adjust the refractive index, the thickness and the optical wavelength of the material of the light exit layer 274. In this embodiment, the material of the light-emitting layer 274 may be Si3N4, SiO2, Si3O4, SiN, or SiNO or the like. In this embodiment, the light-emitting layer 274 can be a dielectric material, and the material composition can be cerium oxide (SiO2), tantalum nitride (SiN) or a mixture of the two materials, and the reflection coefficient is between 1.5 and 2.0.

Please refer to FIG. 2A to FIG. 7 , which are schematic diagrams of several stages of a preferred embodiment of a method for fabricating a vertical cavity surface-emitting laser structure according to the present invention.

As shown in FIG. 2A, it is a schematic diagram of the first stage in the manufacturing method of the vertical cavity surface-emitting laser structure of the present invention. The method for fabricating a vertical cavity surface-emitting laser structure of the present invention firstly provides a laser wafer substrate, which is sequentially formed from bottom to top on the laser wafer substrate: a substrate 10 and a first mirror layer 21 Located on the substrate 10, an active layer 22 is on the first mirror layer 21, and a second mirror layer 23 is on the active layer 22. Then, using a first mask and performing a first mask process, a first mask layer having a first predetermined pattern is formed on an upper surface 240 of the second mirror layer 23, the first predetermined pattern It is a pattern 51 corresponding to the first reticle. As shown in FIG. 2B, it is a schematic diagram of an embodiment of the pattern 51 of the first photomask of the present invention. The pattern 51 of the first reticle includes a central circular area 510 and an annular area 511 surrounding the periphery of the central circular area; wherein the central circular area 510 has a radius r1, and the annular area 511 The radius of the inner circumference is r2, and the radius of the periphery of the annular area 511 is r3. The central circular area 510 of the first mask pattern 51 defines the position of the light window 300 that is covered by the mask 5100 on the upper surface 240 of the second mirror layer 23, and the ring of the first mask pattern 51 The region 511 defines an area where the upper surface 240 of the second mirror layer 23 is covered by the mask 5110 and is not ion implanted. The first mask layer includes the masks 5100, 5110. Next, as shown in FIG. 2A, an ion implantation process is performed to ion-implant the region of the second mirror layer 23 that is not covered by the first mask layer (mask 5100, 5110) to form an ion cloth. The implant layer 24, and a bottom of the ion implant layer 24 is still at a predetermined height from the active layer 22. In this embodiment, a portion of the bottom of the ion implantation effective region may overlap with the oxide layer. The present invention can be used to control modal and confined currents by means of an additional ion implantation zone 24 disposed around the light window 300.

As shown in FIG. 3A, it is a schematic diagram of the second stage in the manufacturing method of the vertical cavity surface-emitting laser structure of the present invention. In the case where the first mask layer 5100, 5110 has not been removed, a second mask is used and a second mask process is performed, the upper surface 240 of the second mirror layer 23 and the first mask A second mask layer having a second predetermined pattern is formed over the layers 5100, 5110, the second predetermined pattern being a pattern 52 corresponding to the second mask. As shown in FIG. 3B, it is a schematic diagram of an embodiment of the pattern 52 of the second photomask of the present invention. The pattern 52 of the second reticle includes a central circular area 520 and a peripheral area 521 surrounding the periphery of the central circular area; wherein the central circular area 520 has a radius R1 within the peripheral area 521 The radius of the circumference is R2. The central circular area 520 of the second mask pattern 52 and the peripheral area 521 define a position at which the upper surface 240 of the second mirror layer 23 is covered by the masks 5200, 5210, and is not covered by the mask 5200, The area covered by 5210 is the location where the first trench 31 will be etched later. The second mask layer includes the masks 5200, 5210.

In this embodiment, the value of the radius R1 of the central circular region 520 of the second mask pattern 52 is the inner radius r2 and the peripheral radius r3 of the annular region 511 of the first mask pattern 51. Between the same, that is, r2 < R1 < r3; and the radius R2 of the inner circumference of the second mask pattern 52 is larger than the annular area 511 of the first mask pattern 51. The radius r3 of the periphery, that is, r3 < R2. Therefore, when performing the two mask process procedures of the first mask and the second mask, the self-alignment effect is obtained, so that the aperture of the oxide layer 231 obtained by the subsequent process is aligned with the aperture of the ion implantation layer 24. The accuracy is increased.

Next, as shown in FIG. 4, it is a schematic diagram of the third stage in the manufacturing method of the vertical cavity surface-emitting laser structure of the present invention. Performing a first etching process to etch the second mirror layer 23, the active layer 22, and a region of the first mirror layer 21 that is not covered by the second mask layer (mask 5200, 5210) to form a a first trench 31, and the first trench 31 extends downward from the upper surface 240 of the second mirror layer 23 through the second mirror layer 23 and the active layer 22 such that a bottom of the first trench 31 is located The first mirror layer 21.

Next, as shown in FIG. 5, it is a schematic diagram of the fourth stage in the manufacturing method of the vertical cavity surface-emitting laser structure of the present invention. An oxidation process is performed to form a horizontally extending oxide layer 231 in the second mirror layer 23 through the first trench 31, and the oxide layer 231 is close to the ion implantation layer 24 in height, even There may be partial overlap, and the oxide layer 231 is located above the active layer 22. Compared with the conventional technique in which the oxidation process of the oxide layer must be performed through the second trench 32 because the structure of the first trench 31 is not provided, the oxidation process of the oxide layer 231 is relatively transparent. The first trench 31 is closer to the light window 300, so that the distance required for oxidation is relatively short, the time required for the oxidation process is also shortened, and the stress aggregation problem of the oxide layer 231 extending due to the long oxidation distance is also reduced. .

Next, as shown in FIG. 6, it is a fifth stage diagram of the method for manufacturing the vertical cavity surface-emitting laser structure of the present invention. A second etching process is performed to form a second trench 32 on the second mirror layer 23, and the second trench 32 extends from the upper surface 240 of the second mirror layer 23 at least through the second mirror. The layer 23 and the oxide layer 231 are such that a bottom portion 321 of the second trench 32 is located at either the active layer 22 or the first mirror layer 21. Also, a contact pad is formed in a predetermined region of the upper surface 240 of the second mirror layer 23 by a metal plating process, that is, a portion of the first contact layer 270 later.

Next, as shown in FIG. 7, it is a sixth stage diagram of the method for manufacturing the vertical cavity surface-emitting laser structure of the present invention. A third etching process is performed to form a third trench 33 recessed downwardly at the bottom portion 321 of the second trench 32, and the third trench 33 extends through the first mirror layer 21 from top to bottom ( Or through the active layer 22 and the first mirror layer 21, a bottom portion 331 of the third trench 33 is located at the substrate 10.

Thereafter, filling the first trench 31 with a dielectric material 26 can provide an effect of reducing the overall capacitance of the vertical cavity surface-emitting laser structure; and forming a suitable region on the laser wafer substrate The light-emitting layer 274, an insulating layer 25, and a metal layer 27 (including the first contact layer 270 and the second contact layer 271, 272, 273). Thereby, the vertical cavity surface-emitting laser structure of the present invention as shown in FIG. 1 can be produced.

In this embodiment, as shown in FIG. 1 , a second land 32 and a third trench 33 may define a land area 30 on the laser wafer substrate, and the second trench 32 and the third Both of the trenches 33 are at least partially surrounding the outer periphery of the land region 300. The land region 300 is formed on the substrate 10 and is composed of at least a portion of the first mirror layer 21, the active layer 22, the second mirror layer 23, and the oxide layer 231. There is a light window 300 at a center of a top surface of the land area 300. The first trench 31 is located in the land region 30 and surrounds at least a portion of the outer periphery of the light window 300 and is spaced apart from the second trench 32 by a distance therebetween. The first trench 31 extends through the second mirror layer 23, the oxide layer 231 and the active layer 22 from the top surface of the land region 30.

In the embodiment, the light-emitting layer 274 is located on the light window 300 of the top surface of the land area 30, and can be used to control light. The ion implant layer 24 is located in the second mirror layer 23 and above the oxide layer 231, but the bottom of the ion implant layer 24 may partially overlap the oxide layer 231, and is located in the land region 30. The ion implant layer 24 is at least a portion between the light window 300 and the first trench 31 and surrounding the outer periphery of the light window 300, and can be used to control modality and localized current.

In the embodiment, the first contact layer 270 is located on the top surface of the land region 30 and is in contact with the upper surface of the second mirror layer 23. The second contact layer 271, 272, 273 is located at least at the bottom 331 of the third trench 33 and at least in contact with the substrate 10, and the second contact layer 271, 272, 273 is the third trench 33 The bottom portion 331 has an inclined surface extending upwardly from the third trench 33 and the second trench 32 to the upper surface of the second mirror layer 23 to make a top of the second contact layer 271, 272, 273 The face is substantially at the same height as the first contact layer 270. Therefore, the first contact layer 270 and the second contact layer 271, 272, 273 of the present invention are not only located on the same surface of the substrate 10, but also at substantially the same height position, which facilitates the subsequent wire bonding process. At least a portion of the first contact layer 270 and the second contact layer 271, 272, 273 are exposed outside the insulating layer 25. The bottom portion 321 of the second trench 32 forms a plane such that the second contact layer 271, 272, 273 forms a horizontally extending state at the bottom portion 321 of the second trench 32. Thereby, not only a stepped double-layered boss structure can be formed, but a larger lower-layer boss can increase the heat-dissipating area and reduce the thermal effect, and at the same time, the inclined surfaces of the second and third trench structures 32, 33 of the two-stage recessed The slope is slowed and a flat surface is formed in the bottom portion 321 of the second trench 32, so that the second contact layers 271, 272, and 273 are less likely to cause gold breakage when plating, sputtering, or vapor deposition of the metal layer.

The above description is only a preferred embodiment of the present invention, and is not intended to limit the scope of the present invention, and the equivalents of the present invention are intended to be included within the scope of the present invention.

Claims (10)

 A vertical cavity surface-emitting laser structure comprising: a substrate; a first mirror layer on the substrate; an active layer on the first mirror layer; and a second mirror layer on the active layer; An oxide layer interposed in the second mirror layer; a land region on the substrate and at least a portion of the first mirror layer, the active layer, the second mirror layer, and the oxide layer Constructed to have a light window at a center of a top surface of the land area; a first trench located in the land area and surrounding at least one of the outer circumferences of the light window The first trench is formed by the top surface of the land region extending at least from the top to the second mirror layer, the oxide layer and the active layer; and a second trench surrounding the outer periphery of the land region At least a portion of the first trench is spaced apart from the first trench, and the second trench extends through the second mirror layer and the oxide layer from top to bottom such that a bottom portion of the second trench is located in the active layer One of the two or the first mirror layer; a third trench surrounding the land area At least a portion of the periphery is recessed downward from the bottom of the second trench, and the third trench extends through the first mirror layer from top to bottom such that a bottom of the third trench is located at the base a dielectric material at least filled in the first trench; a first contact layer on the top surface of the land region and in contact with the second mirror layer; and a second contact layer, at least The bottom of the third trench and at least in contact with the substrate.    The vertical cavity surface-emitting laser structure according to claim 1, wherein the vertical cavity surface-emitting laser structure further comprises an insulating layer covering at least one of an outer surface of the one of the land regions. And at least a portion of the first contact layer and the second contact layer are exposed outside the insulating layer; the first mirror layer is an n-type distributed Bragg reflector (DBR) And the second mirror layer is a p-type distributed Bragg mirror layer; the material of the first mirror layer and the second mirror layer comprises aluminum gallium arsenide (AlGaAs) having a different percentage of aluminum moles, and The oxide layer is aluminum having a relatively highest molar percentage in the second mirror layer; the oxide layer extends at least horizontally from an inner circumference of the first trench toward a center of the land region; the dielectric material is low dielectric property a polymeric material; and the first contact layer and the second contact layer are both metal layers.    The vertical cavity surface-emitting laser structure according to claim 1, further comprising: an ion implantation layer located in the second mirror layer and having a height close to or overlapping with the oxide layer, and The ion implant layer in the region of the land is at least a portion between the light window and the first trench and surrounding an outer periphery of the light window; wherein the first contact layer is Contacting an upper surface of the second mirror layer.    The vertical cavity surface-emitting laser structure according to claim 1, further comprising: a light exiting layer on the light window of the top surface of the land area.    The vertical cavity surface-emitting laser structure according to claim 1, wherein the second contact layer has a bottom portion of the third trench along the third trench and the second trench respectively An inclined surface extends upward to an upper surface of the second mirror layer such that a top surface of the second contact layer is substantially at the same height as the first contact layer; and a bottom portion of the second trench forms a The plane is such that the second contact layer forms a horizontally extending state at the bottom of the second trench.    A method for fabricating a vertical cavity surface-emitting laser structure, comprising the steps of: providing a laser wafer substrate, wherein the semiconductor substrate is sequentially formed by a semiconductor process from bottom to top: a substrate, a first a mirror layer is disposed on the substrate, an active layer is on the first mirror layer, and a second mirror layer is on the active layer; using a first mask and performing a first mask process, in the second An upper surface of the mirror layer forms a first mask layer having a first predetermined pattern, the first predetermined pattern is a pattern corresponding to the first mask; an ion implantation process is performed, the second mirror layer is The region not covered by the first photoresist layer is ion implanted to form an ion implant layer, and a bottom of the ion implant layer is still at a predetermined height from the active layer; the first mask has not been removed yet In the case of a layer, using a second mask and performing a second mask process, forming a second predetermined pattern on the upper surface of the second mirror layer and above the first mask layer a second mask layer, the second predetermined pattern corresponding to the second a pattern of the mask; performing a first etching process, etching the second mirror layer, the active layer, and the region of the first mirror layer not covered by the second mask layer to form a first trench, and The first trench is penetrating from the upper surface of the second mirror layer to the second mirror layer and the active layer such that a bottom portion of the first trench is located at the first mirror layer; an oxidation process is performed so that Forming a horizontally extending oxide layer in the second mirror layer through the first trench, and the oxide layer is close to or overlapping the bottom of the ion implant layer in height; performing a second etching process so as to Forming a second trench on the second mirror layer, and the second trench is extending from the upper surface of the second mirror layer at least through the second mirror layer and the oxide layer, so that one of the second trenches a bottom portion is located at either the active layer or the first mirror layer; and a contact pad is formed on a predetermined region of the upper surface of the second mirror layer by a metal plating process; Etching procedure to form a downward recess at the bottom of the second trench a third trench, and the third trench extends from the top to the bottom through the first mirror layer such that a bottom of the third trench is located at the base; and the first trench is filled with a dielectric Materials, and appropriate regions on the laser wafer substrate, respectively, forming an insulating layer, a first contact layer, and a second contact layer; wherein the second trench and the third trench are available in the laser wafer Forming a land area on the substrate, the second channel and the third channel are both at least a portion of an outer circumference surrounding the land area; the land area is above the substrate, and Forming at least a portion of the first mirror layer, the active layer, the second mirror layer, and the oxide layer, and having a light window at a center of a top surface of the land region; a trench is located in the region of the land and surrounding at least a portion of the outer periphery of the light window and spaced apart from the second trench; the first trench is defined by the top surface of the land region Opening the second mirror layer, the oxide layer and the active layer at least upwardly and downwardly; The first contact layer is located on the top surface of the land area and is in contact with the second mirror layer; the second contact layer is located at least at the bottom of the third trench and at least contacts the substrate, and the first contact layer The second contact layer extends from the bottom of the third trench along the third trench and the second trench respectively to an upper surface of the second mirror layer, so that the second contact layer A top surface is substantially at the same height as the first contact layer; at least a portion of the first contact layer and the second contact layer are exposed outside the insulating layer.    The method for manufacturing a vertical cavity surface-emitting laser structure according to claim 6, wherein: the first mirror layer is an n-type distributed Bragg reflector (DBR), and the first The second mirror layer is a p-type distributed Bragg mirror layer; the material of the first mirror layer and the second mirror layer comprises aluminum gallium arsenide (AlGaAs) having a different percentage of aluminum moles, and the oxide layer is in the The second mirror layer is aluminum having a relatively highest molar percentage; the oxide layer extends at least horizontally from the inner periphery of the first trench toward the center of the land region; the dielectric material is a low dielectric property polymer material And the first contact layer and the second contact layer are both metal layers.    The method of fabricating a vertical cavity surface-emitting laser structure according to claim 6, wherein the ion implantation layer is located in the second mirror layer, and the ion implantation is located in the land region. The layer is at least a portion between the light window and the first trench and surrounding the outer periphery of the light window.    The method for manufacturing a vertical cavity surface-emitting laser structure according to claim 6, further comprising the step of: forming a light-emitting layer on the light window of the top surface of the land area.    The method for manufacturing a vertical cavity surface-emitting laser structure according to claim 6, wherein a plane is formed at the bottom of the second trench, so that the second contact layer is formed at the bottom of the second trench. A state of horizontal extension.