JP2004111575A - Lateral bipolar transistor, semiconductor device having the transistor, and manufacturing method thereof - Google Patents

Abstract

A lateral bipolar transistor capable of improving a current amplification factor and a method for manufacturing the same are provided.
According to the present invention, in a lateral bipolar transistor having a collector region and an emitter region juxtaposed on a base region, the collector region and the emitter region have a P-type or N-type impurity contained in silicon germanium. Was formed by diffusing in the base region.
[Selection diagram] Fig. 1

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a lateral bipolar transistor, a semiconductor device, and a method for manufacturing the same.
[0002]
[Prior art]
With the recent reduction in size and weight of electronic devices, BiCMOS semiconductor devices have been used in which bipolar transistors and CMOS transistors are mixedly mounted on the same semiconductor substrate, and the advantages of both transistors are effectively used. . In such a BiCMOS semiconductor device, in order to be able to manufacture a bipolar transistor and a CMOS transistor on a semiconductor substrate in substantially the same process, a lateral type in which a collector region and an emitter region are juxtaposed above a base region. Bipolar transistors are employed.
[0003]
In the lateral bipolar transistor 100, as shown in FIG. 7, a base region 102 including an N-type epitaxial layer 106 and an N ⁺ buried layer 107 is formed inside a P-type semiconductor substrate 201, and the base region 102 is formed on the base region 102. It has a structure in which a collector region 103 and an emitter region 104 are formed at an interval on the left and right.
[0004]
However, it will be formed in a state in which the collector region 103 and emitter region 104 is close to the ^{N +} buried layer 107, a current to be energized from the collector region 103 to the emitter region 104 from the collector region 103 of the base region 102 ^{N +} buried When current flows through the layer 107, the current amplification factor of the lateral bipolar transistor 100 may be reduced.
[0005]
Therefore, in the conventional lateral bipolar transistor 100, a silicon-germanium mixed crystal region 105 serving as a current path is formed between the collector region 103 and the emitter region 104, and the current from the collector region 103 to the emitter region 104 is supplied to the silicon-germanium mixed crystal. This is performed favorably through the crystal region 105 (for example, see Patent Document 1).
[0006]
The conventional lateral bipolar transistor 100 has been manufactured as follows.
[0007]
First, as shown in FIG. 7A, an N-type epitaxial layer 106 is formed on the surface of a P-type semiconductor substrate 201, and an N ⁺ buried layer is formed between the N-type epitaxial layer 106 and the P-type semiconductor substrate 201. 107 is formed. The N-type epitaxial layer 106 and the N ⁺ buried layer 107 form the base region 102. Note that an element isolation oxide film 108 is formed around the base region 102.
[0008]
Next, as shown in FIG. 7B, an insulating film 109 is formed on the surface of the N-type epitaxial layer 106, and openings 110 and 111 are formed at predetermined positions of the insulating film 109.
[0009]
Next, as shown in FIG. 7C, polysilicon films 112 and 113 are formed in the openings 110 and 111 of the insulating film 109, and a P-type impurity such as boron is implanted into the polysilicon films 112 and 113. Thereafter, heat treatment is performed on the polysilicon films 112 and 113. As a result, the P-type impurities diffuse from the polysilicon films 112 and 113 into the N-type epitaxial layer 106, and the collector region 103 and the emitter region 104 are formed inside the N-type epitaxial layer 106, respectively.
[0010]
Next, as shown in FIG. 7D, germanium is implanted into the N-type epitaxial layer 106 between the collector region 103 and the emitter region 104, and a current path is formed between the collector region 103 and the emitter region 104. A silicon-germanium mixed crystal region 105 is formed.
[0011]
[Patent Document 1]
JP-A-10-308400 (FIG. 1)
[0012]
[Problems to be solved by the invention]
However, in the above-described conventional lateral bipolar transistor, a current path was formed by injecting germanium into the epitaxial layer between the collector region and the emitter region in order to increase the current amplification factor. Since a germanium implantation step is added to the process, the manufacturing process of the lateral bipolar transistor becomes complicated, and the manufacturing cost may increase.
[0013]
This is because the P-type impurity contained in the polysilicon film is diffused into the N-type epitaxial layer to form the collector region and the emitter region, so that the P-type impurity diffuses deeply in the N-type epitaxial layer. As a result, the collector region and the emitter region are formed close to the N ⁺ buried layer of the base region, whereby the current to be passed from the collector region to the emitter region is passed from the collector region to the base region, and the current is amplified. This was to prevent the rate from decreasing.
[0014]
In view of the above, an object of the present invention is to provide a lateral bipolar transistor in which an impurity is diffused shallowly in an epitaxial layer and a good current amplification factor can be secured without forming a separate current path.
[0015]
[Means for Solving the Problems]
That is, according to the first aspect of the present invention, in a lateral bipolar transistor having a collector region and an emitter region juxtaposed on a base region, the collector region and the emitter region are composed of P and Si contained in a silicon germanium layer. And N-type impurities are diffused in the base region.
[0016]
Further, according to the present invention, a lateral bipolar transistor in which a collector region having a first silicon germanium layer above a first base region and an emitter region are arranged side by side, and the second base region is formed by a second base region. In a semiconductor device in which a silicon germanium hetero-coupled bipolar transistor formed of a silicon germanium layer is formed on the same semiconductor substrate, the collector region and the emitter region of the lateral bipolar transistor are formed of the first silicon germanium. The P-type or N-type impurities contained in the layer are formed by diffusing in the first base region.
[0017]
In the present invention according to claim 3, in the present invention according to claim 2, the first silicon germanium layer serving as the collector region and the emitter region of the lateral bipolar transistor, and the silicon germanium hetero-coupled bipolar transistor The second silicon germanium layer serving as the base region of the transistor is simultaneously laminated.
[0018]
According to a fourth aspect of the present invention, in the method for manufacturing a lateral bipolar transistor in which a collector region and an emitter region are formed on a base region at a right and left interval, a silicon germanium layer is laminated on the base region. After that, the collector region and the emitter region are formed by diffusing a P-type or N-type impurity contained in the silicon germanium layer into the base region.
[0019]
Further, in the present invention according to claim 5, a lateral bipolar transistor in which a collector region having a first silicon germanium layer above a first base region and an emitter region are formed at right and left intervals, and In a method for manufacturing a semiconductor device, wherein a silicon germanium hetero-coupled bipolar transistor having a base region formed of a second silicon germanium layer and a silicon germanium hetero-coupled bipolar transistor are formed on the same semiconductor substrate, the second base of the silicon germanium hetero-coupled bipolar transistor is formed. Forming the second base region by laminating the second silicon germanium layer on the region, and laminating the first silicon germanium layer on the first base region of the lateral bipolar transistor; And then this horizontal bipolar transistor The collector region of the lateral bipolar transistor by diffusing a P-type or N-type impurity contained in the first silicon germanium layer laminated on the first base region into the first base region. And forming the emitter region.
[0020]
According to a sixth aspect of the present invention, in the first aspect of the present invention, the first silicon germanium layer serving as the collector region and the emitter region of the lateral bipolar transistor, and the silicon germanium hetero-coupled bipolar transistor And the second silicon germanium layer serving as the second base region.
[0021]
BEST MODE FOR CARRYING OUT THE INVENTION
In the lateral bipolar transistor according to the present invention, a base region including an N-type epitaxial layer and an N ⁺ buried layer is formed inside a P-type semiconductor substrate, and a P-type or N-type impurity is contained above the base region. Silicon germanium is stacked on the left and right at intervals, and then a P-type or N-type impurity contained in each silicon germanium is diffused into the base region to form a collector region and an emitter region.
[0022]
As described above, when the P-type or N-type impurities contained in silicon germanium are diffused into the base region, the diffusion of the P-type or N-type impurities into the base region by the action of germanium can be suppressed.
[0023]
Therefore, the collector region and the emitter region can be formed shallowly in the base region, thereby preventing a current to be conducted between the collector region and the emitter region from flowing into the base region.
[0024]
Therefore, when the thickness of the N-type epitaxial layer is the same as that of the conventional type, the current amplification factor of the lateral bipolar transistor can be improved, and the N-type epitaxial layer can be maintained while maintaining the current amplification factor of the conventional type. The thickness of the layer can also be reduced.
[0025]
When the thickness of the N-type epitaxial layer is reduced, the frequency characteristics of the silicon-germanium hetero-coupled bipolar transistor can be improved when the lateral bipolar transistor and the silicon-germanium hetero-coupled bipolar transistor are formed on the same substrate. it can.
[0026]
Note that as an impurity contained in silicon germanium, a substance having a low diffusion constant in germanium is preferable.
[0027]
Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings.
[0028]
As shown in FIG. 1, in a lateral bipolar transistor 1 according to the present invention, a first base region 5 including an N ⁺ buried layer 3 and an N-type epitaxial layer 4 is formed in a P-type semiconductor substrate 2. A collector layer 6 made of a first silicon-germanium layer containing a P-type impurity and an emitter layer 7 are stacked on the base region 5 at an interval on the left and right, and thereafter, each collector layer 6 and the emitter layer 7 are stacked. Is diffused into the N-type epitaxial layer 4 of the first base region 5 to form the collector region 8 and the emitter region 9.
[0029]
A method for manufacturing the lateral bipolar transistor 1 will be described with reference to FIGS. In the following description, a method for manufacturing a semiconductor device 11 in which the lateral bipolar transistor 1 and the silicon-germanium hetero-coupled bipolar transistor 10 are simultaneously formed on the same semiconductor substrate will be described. In such a silicon germanium hetero-coupled bipolar transistor 10, the second base region 20 is formed of a second silicon germanium layer.
[0030]
First, as a pretreatment, the surface of the P-type semiconductor substrate 2 is sacrificed and oxidized, and then the oxide film is removed using a chemical solution such as hydrofluoric acid. I do.
[0031]
Next, the oxide film on the surface of the P-type semiconductor substrate 2 is removed by dry etching using a resist pattern to form an opening in a region for forming the lateral bipolar transistor 1 and the silicon germanium hetero-coupled bipolar transistor 10. I do.
[0032]
Next, as shown in FIG. 2, N ⁺ buried layers 3 and 12 are formed inside the P-type semiconductor substrate 2 by diffusing antimony (Sb) in a gas phase, and then using a chemical such as hydrofluoric acid. The oxide film on the surface is removed, and N-type epitaxial layers 4 and 13 are formed by an epitaxial method. The N ⁺ buried layer 3 and the N-type epitaxial layer 4 constitute a base region 5 of the lateral bipolar transistor 1.
[0033]
Next, an oxide film 14 is partially formed on the surface of the N-type epitaxial layer 4 by a LOCOS (Local Oxidation of Silicon) method, and the oxide film 14 is oxidized by thermal oxidation in order to remove damage caused when the oxide film 14 is formed. A film 15 is formed.
[0034]
Next, a base extraction layer 16 and a collector extraction layer 17 are respectively formed on the N ⁺ buried layers 3 and 12 by ion implantation using a resist pattern.
[0035]
Next, a P-type element isolation layer 18 is formed by ion implantation using a resist pattern.
[0036]
Next, as shown in FIG. 3, an oxide film is formed by a low-pressure CVD (Chemical Vapor Deposition) method, and a heat treatment is performed in a nitrogen atmosphere. An opening is formed in the oxide film 15 so that the surface of the N-type epitaxial layers 4 and 13 is not damaged by wet etching using, and the N-type epitaxial layers 4 and 13 are exposed.
[0037]
Next, germanium silicon (SiGe) containing boron (B), which is a P-type impurity, is laminated on the surfaces of the N-type epitaxial layers 4 and 13 and the surface of the oxide film 15 by an epitaxial method to form a germanium silicon layer. . At this time, single-crystal germanium silicon is stacked on the surfaces of the N-type epitaxial layers 4 and 13, and polycrystalline germanium silicon is stacked on the surface of the oxide film 15.
[0038]
Next, the germanium silicon layer is formed into a predetermined shape by dry etching using a resist pattern to form the collector layer 6 and the emitter layer 7 of the lateral bipolar transistor 1 and the base region 20 of the silicon germanium hetero-coupled bipolar transistor 10.
[0039]
Next, heat treatment is performed to diffuse the P-type impurities contained in the collector layer 6 and the emitter layer 7 into the N-type epitaxial layer 4 to form diffusion layers 21 and 22. At this time, since the collector layer 6 and the emitter layer 7 are made of germanium silicon, the diffusion of the P-type impurity is suppressed by the action of germanium, whereby the P-type impurity is reduced inside the N-type epitaxial layer 4. It will diffuse shallowly. Here, the collector region 8 is formed by the collector layer 6 and the diffusion layer 21, and the emitter region 9 is formed by the emitter layer 7 and the diffusion layer 22.
[0040]
Next, as shown in FIG. 4, an oxide film 23 is formed by a low pressure CVD method, a heat treatment is performed in a nitrogen atmosphere, and the base region 20 of the silicon germanium hetero-coupled bipolar transistor 10 is dry-etched using a resist pattern. An opening is formed in the upper part of.
[0041]
Next, phosphorus ions (P ⁺ ) are implanted by ion implantation using a resist pattern to form a collector region 24 made of N-type SIC (selective implanted collector) inside the N-type epitaxial layer 13.
[0042]
Next, a polycrystalline silicon film and an oxide film are sequentially formed by a low pressure CVD method, and arsenic (As) is implanted by ion implantation using a resist pattern to form an emitter region 25 above the base region 20.
[0043]
Next, after removing the oxide film using a chemical such as hydrofluoric acid, a new oxide film is formed, heat treatment is performed in a nitrogen atmosphere, and then annealing is performed, and oxidation is performed using a chemical such as hydrofluoric acid. Remove the film.
[0044]
Next, the emitter electrode 26 is formed by forming the polycrystalline silicon film into a predetermined shape by dry etching using a resist pattern.
[0045]
Next, after opening a predetermined portion of the oxide film 23 by dry etching using a resist pattern, a metal film such as cobalt (Co) or titanium (Ti) is formed, and titanium nitride (TiN) is sputtered. Thereafter, heat treatment is performed in a nitrogen atmosphere to form the metal silicide 27.
[0046]
Next, the unreacted metal film formed on the surface of the oxide film 23 is removed using a chemical such as ammonia peroxide, and heat treatment is performed in a nitrogen atmosphere to reduce the resistance of the metal silicide 27.
[0047]
Next, as shown in FIG. 5, after forming a silicon nitride (Si ₃ N ₄ ) film 28 using a low pressure CVD method, an oxide film 29 is formed using a low pressure CVD method.
[0048]
Next, an interlayer film 30 is formed on the surface of the P-type semiconductor substrate 2, a tungsten plug 31 is formed at a predetermined location, and then a predetermined wiring is provided.
[0049]
According to the manufacturing method described above, the semiconductor device 11 in which the lateral bipolar transistor 1 and the silicon-germanium hetero-coupled bipolar transistor 10 are simultaneously formed on the same semiconductor substrate can be manufactured.
[0050]
In the above description, the case where the PNP-type lateral bipolar transistor 1 is formed has been described. However, the NPN-type lateral bipolar transistor 32 can be manufactured by only partially changing the manufacturing method.
[0051]
That is, when manufacturing the NPN type lateral bipolar transistor 32, as shown in FIG. 6, a base region 33 composed of a P-type well layer is formed inside the N-type epitaxial layer 4, and an N-type epitaxial layer 4 is formed. Germanium silicon (SiGe) containing phosphorus (P) as an impurity is stacked on the surface of the base region 33 to form a collector layer 34 and an emitter layer 35, and then subjected to a heat treatment to form the collector layer 34 and the emitter layer 35. Are diffused into the base region 33 to form diffusion layers 36 and 37. Also at this time, since the collector layer 34 and the emitter layer 35 are made of germanium silicon, the diffusion of N-type impurities is suppressed by the action of germanium. Will do. Here, a collector region 38 is formed by the collector layer 34 and the diffusion layer 36, and an emitter region 39 is formed by the emitter layer 35 and the diffusion layer 37.
[0052]
Other manufacturing steps other than the above manufacturing steps are the same as those for manufacturing the PNP type lateral bipolar transistor 1 described above. In FIG. 6, the same steps as those in FIGS. 1 to 5 are denoted by the same reference numerals.
[0053]
【The invention's effect】
The present invention is implemented in the form described above, and has the following effects.
[0054]
That is, according to the present invention, in a lateral bipolar transistor having a collector region and an emitter region juxtaposed on a base region, the collector region and the emitter region are made of silicon germanium containing P-type or N-type impurities. Since the region is formed, diffusion of impurities inside the base region can be suppressed by the action of germanium, whereby the collector region and the emitter region can be formed shallowly in the base region and the collector region can be formed. It is possible to prevent a current to be conducted between the transistor and the emitter region from flowing into the base region, so that the current amplification factor of the lateral bipolar transistor can be improved.
[0055]
Further, in the present invention according to claim 2, a lateral bipolar transistor having a collector region and an emitter region juxtaposed on a base region and a silicon germanium hetero-coupled bipolar transistor having a base region formed of silicon germanium are the same. In a semiconductor device formed on a semiconductor substrate, since the collector region and the emitter region of the lateral bipolar transistor are formed of silicon germanium containing P-type or N-type impurities, the impurities diffuse inside the base region. Can be suppressed by the action of germanium, whereby the collector region and the emitter region can be formed shallowly in the base region, thereby improving the frequency characteristics of the silicon germanium hetero-coupled bipolar transistor formed on the same semiconductor substrate. Let Therefore, even if the thickness of the N-type epitaxial layer formed on the semiconductor substrate is reduced, the distance between the collector region and the emitter region of the lateral bipolar transistor and the N-type epitaxial layer can be maintained. A reduction in the current amplification factor of the lateral bipolar transistor due to the thinning can be suppressed.
[0056]
Further, in the present invention according to claim 3, since silicon germanium serving as a collector region and an emitter region of a lateral bipolar transistor and silicon germanium serving as a collector region of a silicon germanium hetero-coupled bipolar transistor are simultaneously laminated, A semiconductor device in which a lateral bipolar transistor and a silicon germanium hetero-coupled bipolar transistor are mixedly mounted on the same semiconductor substrate can be easily manufactured, and the manufacturing cost can be reduced.
[0057]
According to a fourth aspect of the present invention, in the method for manufacturing a lateral bipolar transistor in which a collector region and an emitter region are formed on a base region at a right and left interval, the method further comprises the step of stacking silicon germanium on the base region. Since the collector region and the emitter region are formed by diffusing the P-type or N-type impurity contained in the silicon germanium into the base region, the diffusion of the impurity inside the base region is prevented by the action of germanium. Therefore, the collector region and the emitter region can be formed shallowly in the base region, and current flowing between the collector region and the emitter region can be prevented from flowing into the base region. Can produce horizontal bipolar transistors with improved current amplification. It can be.
[0058]
Further, in the present invention according to claim 5, a lateral bipolar transistor in which a collector region and an emitter region are formed on the base region at right and left intervals, and a silicon germanium hetero-coupled bipolar transistor in which the base region is formed of silicon germanium In a method of manufacturing a semiconductor device in which a transistor and a transistor are formed on the same semiconductor substrate, a base region is formed by stacking silicon germanium on a collector region of a silicon germanium hetero-coupled bipolar transistor, and a base of a lateral bipolar transistor is formed. Silicon germanium is stacked on the upper portion of the region, and then, P-type or N-type impurities contained in the silicon germanium stacked on the upper portion of the base region of the lateral bipolar transistor are diffused into the base region. Since the collector region and the emitter region of the lateral bipolar transistor are formed, the diffusion of impurities inside the base region can be suppressed by the action of germanium, whereby the collector region and the emitter region are formed in the base region. Can be formed shallowly. Therefore, even if the thickness of the N-type epitaxial layer formed on the semiconductor substrate is reduced in order to improve the frequency characteristics of the silicon germanium hetero-coupled bipolar transistor formed on the same semiconductor substrate, The distance between the collector region and the emitter region of the bipolar transistor and the N-type epitaxial layer can be maintained, and the reduction in the current amplification factor of the lateral bipolar transistor due to the thinning of the N-type epitaxial layer can be suppressed. Bipolar tiger It is possible to manufacture a semiconductor device with improved characteristics of registers and silicon-germanium heterojunction bipolar transistor.
[0059]
In the present invention according to claim 6, silicon germanium serving as a collector region and an emitter region of a lateral bipolar transistor and silicon germanium serving as a collector region of a silicon germanium hetero-coupled bipolar transistor are simultaneously laminated. A semiconductor device in which a lateral bipolar transistor and a silicon germanium hetero-coupled bipolar transistor are mixedly mounted on the same semiconductor substrate can be easily manufactured, and the manufacturing cost can be reduced.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view illustrating a lateral bipolar transistor according to the present invention.
FIG. 2 is an explanatory view illustrating a method for manufacturing a semiconductor device.
FIG. 3 is an explanatory view illustrating a method for manufacturing a semiconductor device.
FIG. 4 is an explanatory view illustrating a method for manufacturing a semiconductor device.
FIG. 5 is an explanatory view illustrating a method for manufacturing a semiconductor device.
FIG. 6 is a cross-sectional view illustrating an NPN lateral bipolar transistor.
FIG. 7 is a cross-sectional view showing a conventional lateral bipolar transistor.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Lateral bipolar transistor 2 P-type semiconductor substrate 3, 12 N ⁺ buried layer 4, 13 N-type epitaxial layer 5 Base region 6 Collector layer 7 Emitter layer 8 Collector region 9 Emitter region 10 Silicon germanium hetero-coupled bipolar transistor 11 Semiconductor device 14, Reference Signs List 15 oxide film 16 base extraction layer 17 collector extraction layer 18 p-type element isolation layer 20 base region 21, 22 diffusion layer 23 oxide film 24 collector region 25 emitter region 26 emitter electrode 27 metal silicide 28 silicon nitride (Si ₃ N ₄ ) film 29 oxide film 30 interlayer film 31 tungsten plug

Claims (6)

In a lateral bipolar transistor having a collector region and an emitter region juxtaposed on a base region,
A lateral bipolar transistor, wherein the collector region and the emitter region are formed by diffusing a P-type or N-type impurity contained in a silicon germanium layer in the base region. A lateral bipolar transistor in which a collector region and an emitter region each having a first silicon germanium layer above a first base region are arranged side by side; and a silicon germanium heterostructure in which a second base region is formed by a second silicon germanium layer. In a semiconductor device formed by forming a coupling bipolar transistor on the same semiconductor substrate,
The collector region and the emitter region of the lateral bipolar transistor are formed by diffusing a P-type or N-type impurity contained in the first silicon germanium layer in the first base region. Semiconductor device. The first silicon germanium layer serving as the collector region and the emitter region of the lateral bipolar transistor and the second silicon germanium layer serving as the base region of the silicon germanium hetero-coupled bipolar transistor are simultaneously laminated. 3. The semiconductor device according to claim 2, wherein: In a method of manufacturing a lateral bipolar transistor in which a collector region and an emitter region are formed on a base region at right and left intervals,
After laminating a silicon germanium layer on the base region, forming the collector region and the emitter region by diffusing a P-type or N-type impurity contained in the silicon germanium layer into the base region. A method for manufacturing a lateral bipolar transistor. A lateral bipolar transistor in which a collector region having a first silicon germanium layer above a first base region and an emitter region are formed at right and left intervals, and a second base region is formed of a second silicon germanium layer Forming a silicon germanium hetero-coupled bipolar transistor and the same on the same semiconductor substrate, a method of manufacturing a semiconductor device,
The second base region is formed by stacking the second silicon germanium layer on the second base region of the silicon germanium hetero-coupled bipolar transistor, and the first base of the lateral bipolar transistor is formed. The first silicon germanium layer is stacked on the base region, and then the P-type or N-type is included in the first silicon germanium layer stacked on the first base region of the lateral bipolar transistor. Forming the collector region and the emitter region of the lateral bipolar transistor by diffusing an impurity of the type into the first base region. The first silicon germanium layer serving as the collector region and the emitter region of the lateral bipolar transistor and the second silicon germanium layer serving as the second base region of the silicon germanium hetero-coupled bipolar transistor are simultaneously laminated. 6. The method for manufacturing a semiconductor device according to claim 5, wherein

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