TWI778278B - Negative ion irradiation device and control method of negative ion irradiation device - Google Patents

Abstract

The present invention provides a negative ion irradiation apparatus and a control method of the negative ion irradiation apparatus capable of improving the production efficiency and quality of compound semiconductors. The control unit (50) controls the gas supply unit (40) to supply gas into the vacuum chamber (10). The gas supply unit (40) supplies a gas containing the same element as the ions forming the compound semiconductor (11). Therefore, the same element as the ions forming the compound semiconductor (11) is present in the vacuum chamber (10). Furthermore, the control unit (50) generates plasma (P) and electrons in the vacuum chamber (10) by controlling the plasma generation unit (14), and stops the generation of the plasma (P), thereby generating electrons from the electrons. Negative ions are generated with the gas, and the negative ions are irradiated on the compound semiconductor (11).

Description

Negative ion irradiation device and control method of negative ion irradiation device

This application claims priority based on Japanese Patent Application No. 2018-134880 filed on July 18, 2018. The entire contents of the Japanese application are incorporated in this specification by reference. The present invention relates to a negative ion irradiation device and a control method of the negative ion irradiation device.

Conventionally, the compound semiconductor disclosed in Patent Document 1 has been known. Crystal defects increase on the single crystal substrate constituting the compound semiconductor. In Patent Document 1, an attempt is made to reduce crystal defects of a single crystal substrate by designing a manufacturing method. (prior art literature) (patent literature) Patent Document 1: Japanese Patent Application Laid-Open No. 2014-22711

(Problem to be solved by the present invention) However, when manufacturing a single crystal substrate, even if a manufacturing method is designed, it is difficult to prevent the generation of crystal defects. In addition, when a crystal defect is generated on a single crystal substrate, there is no practical method for filling the crystal defect. Therefore, the crystal defects of the single crystal substrate are used as they are. The grade (quality) of the single crystal substrate is determined according to the amount of crystal defects, and the use is determined according to the grade. Therefore, there is a problem that the production efficiency of compound semiconductors is lowered due to the limited number of single crystal substrates that can be used for compound semiconductors. On the other hand, there is a problem that, when a low-grade single crystal substrate is used as a compound semiconductor, the quality of the compound semiconductor is lowered. Therefore, an object of the present invention is to provide a negative ion irradiation apparatus and a control method of the negative ion irradiation apparatus which can improve the production efficiency and quality of compound semiconductors. (means to solve the problem) In order to solve the above-mentioned problems, a negative ion irradiation apparatus according to the present invention irradiates a compound semiconductor with negative ions. The negative ion irradiation apparatus includes: a chamber for generating negative ions inside; ; a plasma generating unit for generating plasma and electrons in the chamber; an arrangement unit for arranging compound semiconductors; and a control unit for controlling the negative ion irradiation device, the control unit controls the gas supply unit to supply gas into the chamber, and the control unit controls the electricity The plasma generation unit generates plasma and electrons in the chamber, and stops the generation of the plasma to generate negative ions from the electrons and the gas, and irradiates the compound semiconductor with the negative ions. In the negative ion irradiation apparatus of this invention, a control part controls a gas supply part, and supplies a gas into a chamber. The gas supply unit supplies a gas containing the same element as the ions forming the compound semiconductor. Therefore, the same element as the ion forming the compound semiconductor exists in the chamber. Furthermore, the control unit controls the plasma generation unit to generate plasma and electrons in the chamber, and stops the generation of the plasma to generate negative ions from the electrons and the gas, and irradiate the negative ions onto the compound semiconductor. Thereby, negative ions of the same element as the ions forming the compound semiconductor are irradiated to the compound semiconductor. Thereby, the negative ions enter the crystal defects derived from the anions in the compound semiconductor, so that the crystal defects can be filled. In this way, the crystal defects of the compound semiconductor can be filled, so that the quality of the compound semiconductor can be improved. Furthermore, even if the grade as a compound semiconductor is insufficient before negative ion irradiation, the quality can be improved by negative ion irradiation, so that the need for preliminarily screening the grade of the single crystal substrate can be reduced. With the above, the production efficiency and quality of compound semiconductors can be improved. The control method of the negative ion irradiation apparatus of the present invention is a control method of the negative ion irradiation apparatus that irradiates the compound semiconductor with negative ions. The negative ion irradiation apparatus includes: a chamber for generating negative ions inside; and a gas supply unit for supplying ions containing and forming compound semiconductors. The gas of the same element; the plasma generating part, which generates plasma and electrons in the chamber; the disposing part, disposing the compound semiconductor; The gas supply unit is controlled by the control unit to supply gas into the chamber; and the negative ion irradiation process is controlled by the control unit to control the plasma generation unit to generate plasma and electrons in the chamber, and by stopping the generation of the plasma, the The electrons and the gas generate negative ions, and the negative ions are irradiated to the compound semiconductor. According to the control method of the negative ion irradiation apparatus of the present invention, the same functions and effects as those of the negative ion irradiation apparatus described above can be obtained. (effect of invention) The present invention can provide a negative ion irradiation apparatus and a control method of the negative ion irradiation apparatus capable of improving the production efficiency and quality of compound semiconductors.

Hereinafter, referring to the attached drawings, the negative ion irradiation apparatus according to one embodiment of the present invention will be described. In addition, in the drawings, the same elements are denoted by the same reference numerals, and overlapping descriptions are omitted. First, referring to FIGS. 1 and 2 , the configuration of the negative ion irradiation apparatus according to the embodiment of the present invention will be described. 1 and 2 are schematic cross-sectional views showing the configuration of the negative ion irradiation apparatus of the present embodiment. FIG. 1 shows an operating state when plasma is generated, and FIG. 2 shows an operating state when plasma is stopped. As shown in FIGS. 1 and 2 , the negative ion irradiation apparatus 1 of the present embodiment is an apparatus for applying a film-forming technique for a so-called ion plating method to negative ion irradiation. In addition, for convenience of description, the XYZ coordinate system is shown in FIGS. 1 and 2 . The Y-axis direction is the direction in which the compound semiconductor is transported, which will be described later. The X-axis direction is the thickness direction of the compound semiconductor. The Z-axis direction is a direction orthogonal to the Y-axis direction and the X-axis direction. The negative ion irradiation apparatus 1 may be a so-called horizontal negative ion irradiation apparatus in which the compound semiconductor 11 is arranged and transported in the vacuum chamber 10 so that the thickness direction of the compound semiconductor 11 becomes a substantially vertical direction. At this time, the Z-axis and Y-axis directions are the horizontal directions, and the X-axis direction is the vertical direction and the plate thickness direction. In addition, the negative ion irradiation device 1 may be a so-called vertical negative ion irradiation device, that is, the compound semiconductor 11 may have a horizontal direction (X-axis direction in FIGS. The compound semiconductor 11 is placed in the vacuum chamber 10 and transported in a state where the semiconductor 11 is upright or inclined from the upright state. At this time, the X-axis direction is the horizontal direction, the thickness direction of the compound semiconductor 11 , the Y-axis direction is the horizontal direction, and the Z-axis direction is the vertical direction. The negative ion irradiation apparatus according to one embodiment of the present invention will be described below by taking a horizontal negative ion irradiation apparatus as an example. The negative ion irradiation apparatus 1 includes a vacuum chamber 10 , a transport mechanism (arrangement unit) 3 , a plasma generation unit 14 , a gas supply unit 40 , a circuit unit 34 , a voltage application unit 90 , and a control unit 50 . The vacuum chamber 10 is a member for accommodating the compound semiconductor 11 and performing a film formation process. The vacuum chamber 10 has a transport chamber 10 a for transporting the compound semiconductor 11 , a generation chamber 10 b for generating negative ions, and a plasma port for receiving the plasma P irradiated in a beam form from the plasma gun 7 into the vacuum chamber 10 10c. The transport chamber 10a, the generation chamber 10b, and the plasma port 10c communicate with each other. The conveyance chamber 10a is set along a predetermined conveyance direction (arrow A in the figure) (along the Y axis). In addition, the vacuum chamber 10 is made of a conductive material and connected to the ground potential. A heating unit 30 for heating the compound semiconductor 11 is provided in the transfer chamber 10a. The heating unit 30 is provided on the upstream side in the conveyance direction of the conveyance chamber 10a and the communication portion with the production chamber 10b. Therefore, the negative ions from the generation chamber 10b are irradiated to the compound semiconductor 11 in a heated state. The production chamber 10b has, as the wall portion 10W, a pair of side walls along the conveyance direction (arrow A), a pair of side walls 10h and 10i along a direction (Z-axis direction) intersecting the conveyance direction (arrow A), and a pair of side walls 10h and 10i along the conveyance direction (arrow A). The bottom wall 10j arranged to cross the direction. The conveying mechanism 3 conveys the compound semiconductor holding member 16 that holds the compound semiconductor 11 in a state of being opposed to the production chamber 10b in the conveying direction (arrow A). The conveying mechanism 3 functions as an arrangement portion for arranging the compound semiconductor 11 . For example, the compound semiconductor holding member 16 is a frame that holds the outer peripheral edge of the compound semiconductor 11 . The conveying mechanism 3 is constituted by a plurality of conveying rollers 15 provided in the conveying chamber 10a. The conveyance rollers 15 are arranged at equal intervals in the conveyance direction (arrow A), and are conveyed in the conveyance direction (arrow A) while supporting the compound semiconductor holding member 16 . In addition, the compound semiconductor 11 is a plate-shaped substrate. The material and the like of the compound semiconductor 11 will be described later. Next, the configuration of the plasma generating unit 14 will be described in detail. The plasma generating unit 14 generates plasma and electrons in the vacuum chamber 10 . The plasma generating unit 14 includes a plasma gun 7 , a steering coil 5 , and a hearth mechanism 2 . The plasma gun 7 is, for example, a pressure gradient type plasma gun, and its main body is connected to the generation chamber 10b through a plasma port 10c provided on the side wall of the generation chamber 10b. Plasma gun 7 generates plasma P in vacuum chamber 10 . The plasma P generated in the plasma gun 7 is emitted from the plasma port 10c into the generation chamber 10b in the form of a beam. Thereby, the plasma P is generated in the generation chamber 10b. One end of the plasma gun 7 is closed by the cathode 60 . A first intermediate electrode (grid) 61 and a second intermediate electrode (grid) 62 are arranged concentrically between the cathode 60 and the plasma port 10c. A ring-shaped permanent magnet 61 a for converging the plasma P is built in the first intermediate electrode 61 . An electromagnet coil 62 a is also built in the second intermediate electrode 62 for the purpose of converging the plasma P. As shown in FIG. The plasma gun 7 intermittently generates plasma P in the generation chamber 10b when generating negative ions. Specifically, the plasma gun 7 is controlled to intermittently generate the plasma P in the generation chamber 10b by the control unit 50 described later. This control will be described in detail in the description of the control unit 50 . The steering coil 5 is provided around the plasma port 10c where the plasma gun is mounted. The steering coil 5 guides the plasma P into the generation chamber 10b. The steering coil 5 is excited by a steering coil power supply (not shown). The hearth mechanism 2 is a mechanism for guiding the plasma P from the plasma gun to a desired position. The hearth mechanism 2 has the main hearth 17 and the ring hearth 6 . When film formation is performed using the negative ion irradiation apparatus 1, the main hearth 17 functions as an anode for holding the film formation material. However, when the negative ion generation is performed, the plasma is guided to the ring hearth 6 so that the plasma P is not guided to the film-forming material. Therefore, when the negative ion irradiation apparatus 1 does not perform film formation but only performs negative ion irradiation, the film formation material does not need to be held by the main hearth 17 . Alternatively, the hearth mechanism 2 only needs to have a configuration in which only the plasma P is guided. The ring hearth 6 is an anode with an electromagnet for inducing the plasma P. The ring hearth 6 is arranged around the filling portion 17 a of the main hearth 17 . The ring hearth 6 has an annular coil 9 , an annular permanent magnet portion 20 , and an annular container 12 , and the coil 9 and the permanent magnet portion 20 are accommodated in the container 12 . In the present embodiment, the coil 9 and the permanent magnet portion 20 are sequentially provided in the X-axis negative direction when viewed from the conveying mechanism 3 , but the permanent magnet portion 20 and the coil 9 may be sequentially provided in the X-axis negative direction. The gas supply unit 40 is arranged outside the vacuum chamber 10 . The gas supply part 40 supplies the gas into the vacuum chamber 10 through the gas supply port 41 provided in the side wall (for example, the side wall 10h) of the production chamber 10b. Specific examples of the gas will be described later. The position of the gas supply port 41 is preferably a position near the boundary between the generation chamber 10b and the transfer chamber 10a. At this time, since the gas from the gas supply unit 40 can be supplied to the vicinity of the boundary between the generation chamber 10b and the transport chamber 10a, the generation of negative ions, which will be described later, is performed in the vicinity of the boundary. Therefore, the generated negative ions can be appropriately injected into the compound semiconductor 11 in the transport chamber 10a. In addition, the position of the gas supply port 41 is not limited to the vicinity of the boundary of the generation chamber 10b and the transfer chamber 10a. The circuit unit 34 includes a variable power supply 80 , a first wiring 71 , a second wiring 72 , resistors R1 to R4 , and short-circuit switches SW1 and SW2 . The variable power supply 80 applies a negative voltage to the cathode 60 of the plasma gun 7 and a positive voltage to the main hearth 17 of the hearth mechanism 2 across the vacuum chamber 10 at ground potential. Thereby, the variable power supply 80 generates a potential difference between the cathode 60 of the plasma gun 7 and the main hearth 17 of the hearth mechanism 2 . The first wiring 71 electrically connects the cathode 60 of the plasma gun 7 and the negative potential side of the variable power supply 80 . The second wiring 72 electrically connects the main hearth 17 (anode) of the hearth mechanism 2 and the positive potential side of the variable power source 80 . One end of the resistor R1 is electrically connected to the first intermediate electrode 61 of the plasma gun 7 , and the other end is electrically connected to the variable power supply 80 via the second wiring 72 . That is, the resistor R1 is connected in series between the first intermediate electrode 61 and the variable power source 80 . One end of the resistor R2 is electrically connected to the second intermediate electrode 62 of the plasma gun 7 , and the other end is electrically connected to the variable power supply 80 via the second wiring 72 . That is, the resistor R2 is connected in series between the second intermediate electrode 62 and the variable power source 80 . One end of the resistor R3 is electrically connected to the wall portion 10W of the generation chamber 10b, and the other end is electrically connected to the variable power supply 80 via the second wiring 72 . That is, the resistor R3 is connected in series between the wall portion 10W of the generation chamber 10b and the variable power source 80 . One end of the resistor R4 is electrically connected to the ring hearth 6 , and the other end is electrically connected to the variable power supply 80 via the second wiring 72 . That is, the resistor R4 is connected in series between the ring hearth 6 and the variable power source 80 . The short-circuit switches SW1 and SW2 are switching parts that are switched to ON/OFF (on/off) states by receiving a command signal from the control part 50 , respectively. The short-circuit switch SW1 is connected in parallel with the resistor R2. The short-circuit switch SW1 is in an OFF state when the plasma P is generated. Thereby, since the second intermediate electrode 62 and the variable power supply 80 are electrically connected to each other via the resistor R2 , it is difficult for current to flow between the second intermediate electrode 62 and the variable power supply 80 . As a result, the plasma P from the plasma gun 7 is emitted into the vacuum chamber 10 . In addition, when the plasma P from the plasma gun 7 is emitted into the vacuum chamber 10 , the current may be made difficult to flow to the first intermediate electrode 61 instead of the case where the current is difficult to flow to the second intermediate electrode 62 . At this time, the short-circuit switch SW1 is not connected to the side of the second intermediate electrode 62 but is connected to the side of the first intermediate electrode 61 . On the other hand, when the plasma P is stopped, the short-circuit switch SW1 is in the ON state. As a result, the electrical connection between the second intermediate electrode 62 and the variable power supply 80 is short-circuited, so that current flows between the second intermediate electrode 62 and the variable power supply 80 . That is, the short-circuit current flows to the plasma gun 7 . As a result, the plasma P from the plasma gun 7 is not emitted into the vacuum chamber 10 . When negative ions are generated, the control unit 50 switches the ON/OFF state of the short-circuit switch SW1 at predetermined intervals, whereby the plasma P from the plasma gun 7 is intermittently generated in the vacuum chamber 10 . That is, the short-circuit switch SW1 is a switching portion that switches the supply and cutoff of the plasma P into the vacuum chamber 10 . The short-circuit switch SW2 is connected in parallel with the resistor R4. The short-circuit switch SW2 is switched ON/OFF by the control unit 50 depending on whether to guide the plasma P to the main hearth 17 side or to the ring hearth 6 side. When the short-circuit switch SW2 is in the ON state, since the electrical connection between the ring hearth 6 and the variable power source 80 is short-circuited, current flows more easily to the ring hearth 6 than to the main hearth 17 . Thereby, the plasma P is easily guided to the ring hearth 6 . On the other hand, if the short-circuit switch SW2 is in the OFF state, the ring hearth 6 and the variable power supply 80 are electrically connected through the resistor R4, so that the current flows more easily to the main hearth 17 than the ring hearth 6, so that plasma P is easily guided to the main hearth 17 side. In addition, when negative ions are generated, the short-circuit switch SW2 is kept in the ON state. When the negative ion irradiation apparatus 1 is not performing film formation, the short-circuit switch SW2 can be kept in the ON state. The voltage applying unit 90 can apply a positive voltage to the compound semiconductor (object) 11 after film formation. The voltage applying unit 90 includes the bias circuit 35 and the trolley wire 18 . The bias circuit 35 is a circuit for applying a positive bias to the compound semiconductor 11 after film formation. The bias circuit 35 includes a bias power supply 27 for applying a positive bias voltage (hereinafter, simply referred to as "bias") to the compound semiconductor 11, a third wiring 73 for electrically connecting the bias power supply 27 and the trolley wire 18, and a third wiring 73 provided on the 3. The short-circuit switch SW3 of the wiring 73. The bias power supply 27 applies a voltage signal (periodic electrical signal) that is a rectangular wave that periodically increases or decreases as a bias. The bias power supply 27 is configured to be able to change the frequency of the applied bias under the control of the control unit 50 . One end of the third wiring 73 is connected to the positive potential side of the bias power supply 27 , and the other end is connected to the trolley wire 18 . Thereby, the third wiring 73 electrically connects the trolley wire 18 and the bias power supply 27 . The short-circuit switch SW3 is connected in series between the trolley wire 18 and the positive potential side of the bias power supply 27 via the third wiring 73 . The short-circuit switch SW3 is a switching portion that switches whether or not a bias voltage is applied to the trolley wire 18 . The ON/OFF state of the short-circuit switch SW3 is switched by the control unit 50 . The short-circuit switch SW3 is turned on at a predetermined timing when negative ions are generated. When the short-circuit switch SW3 is in the ON state, the trolley wire 18 and the positive potential side of the bias power supply 27 are electrically connected to each other, and a bias voltage is applied to the trolley wire 18 . On the other hand, the short-circuit switch SW3 is in the OFF state at a predetermined timing when negative ions are generated. When the short-circuit switch SW3 is in the OFF state, the trolley wire 18 and the bias power supply 27 are electrically disconnected from each other, and the trolley wire 18 is not biased. The trolley wire 18 is a wire for supplying power to the compound semiconductor holding member 16 . The trolley wire 18 is provided to extend in the conveyance direction (arrow A) in the conveyance chamber 10a. The trolley wire 18 supplies power to the compound semiconductor holding member 16 through the power feeding brush 42 by being in contact with the power feeding brush 42 provided on the compound semiconductor holding member 16 . The trolley wire 18 is formed of, for example, a stainless steel wire or the like. The control part 50 is an apparatus which controls the whole of the negative ion irradiation apparatus 1, and is provided with the ECU (Electronic Control Unit: Electronic Control Unit) which manages the whole apparatus. ECU has CPU [Central Processing Unit: Central Processing Unit], ROM [Read Only Memory: Read Only Memory], RAM [Random Access Memory: Random Access Memory], CAN [Controller Area Network: Controller Area Network] ] Electronic control unit of communication circuit, etc. In the ECU, various functions are realized by, for example, loading the program stored in the ROM into the RAM, and executing the program loaded into the RAM by the CPU. The ECU may be composed of a plurality of electronic units. The control unit 50 is arranged outside the vacuum chamber 10 . Further, the control unit 50 includes a gas supply control unit 51 that controls the gas supply by the gas supply unit 40 , a plasma control unit 52 that controls the generation of the plasma P by the plasma generation unit 14 , and a voltage by the voltage applying unit 90 . The applied voltage control section 53 . The gas supply control unit 51 controls the gas supply unit 40 to supply the gas into the production chamber 10b. Next, the plasma control unit 52 of the control unit 50 controls the plasma generation unit 14 to intermittently generate the plasma P from the plasma gun 7 in the generation chamber 10b. For example, the control unit 50 intermittently generates the plasma P from the plasma gun 7 in the generation chamber 10b by switching the ON/OFF state of the short-circuit switch SW1 at predetermined intervals. When the short-circuit switch SW1 is in the OFF state (the state in FIG. 1 ), since the plasma P from the plasma gun 7 is emitted into the generation chamber 10b, the plasma P is generated in the generation chamber 10b. The plasma P includes neutral particles, positive ions, negative ions (when a negative gas such as oxygen is present), and electrons as constituent substances. Therefore, electrons are generated in the generation chamber 10b. When the short-circuit switch SW1 is in the ON state (the state in FIG. 2 ), since the plasma P from the plasma gun 7 is not emitted into the generation chamber 10b, the electron temperature of the plasma P in the generation chamber 10b drops sharply. Therefore, electrons are easily attached to the particles of the gas supplied into the generation chamber 10b. Thereby, negative ions are efficiently generated in the generation chamber 10b. The control unit 50 controls the application of the voltage by the voltage application unit 90 . The control unit 50 applies a voltage through the voltage application unit 90 at a predetermined timing (eg, the timing of stopping the plasma P). In addition, the timing for starting the application of the voltage by the voltage applying unit 90 is preset by the control unit 50 . By applying a positive bias voltage to the compound semiconductor 11 by the voltage applying unit 90 , the negative ions in the vacuum chamber 10 are guided to the compound semiconductor 11 . Thereby, the compound semiconductor is irradiated with negative ions. Here, the relationship between the compound semiconductor 11 and negative ions will be described. The compound semiconductor 11 is formed of a cation (Cation) and an anion (Anion). Anion containing the same element as the anion forming the compound semiconductor 11 is irradiated with respect to the compound semiconductor 11 . In addition, the gas supplied by the gas supply unit 40 contains the same element as the anion forming the compound semiconductor 11 . In addition, the gas also includes a rare gas such as Ar. For example, when the compound semiconductor 11 is formed of ZnO, Ga ₂ O ₃ or the like, negative ions such as O ^- are irradiated. The gas of the gas supply unit 40 contains O ₂ and the like. When the compound semiconductor 11 is formed of AlN, GaN, or the like, negative ions of nitrides such as NH ⁻ are irradiated. In addition, the implanted H is removed by annealing. The gas of the gas supply unit 40 contains NH ₂ , NH ₄ and the like. In addition, when the compound semiconductor 11 is formed of SiC or the like, negative ions such as C ⁻ and Si ⁻ are irradiated. The gas of the gas supply unit 40 contains C ₂ H ₆ , SiH ₄ and the like. In addition, when the compound semiconductor 11 is SiC, since Si can also function as a negative ion, the cation side can also be irradiated as a negative ion. In addition, electron affinity tends to be positive atoms, and molecules tend to be negative ions. Therefore, when such anions of atoms and molecules are contained in the compound semiconductor 11, negative ions containing the same atoms and molecules can be irradiated. For example, H, He, C, O, F, Si, S, Cl, Br, I, _H2 , _O2 , Cl2, _Br2 , _I2 , _CH , OH, CN , HCl, HBr, NH ₂ , N ₂ O, NO ₂ , CCl ₄ , SF ₆ , etc. Next, with reference to FIG. 3, the control method of the negative ion irradiation apparatus 1 is demonstrated. FIG. 3 is a flowchart showing a control method of the negative ion irradiation apparatus 1 of the present embodiment. In addition, here, the compound semiconductor 11 is formed of ZnO, and the case where the negative ion ^of O- is irradiated is demonstrated as an example. As shown in FIG. 3 , the control method of the negative ion irradiation apparatus 1 includes a gas supply process S10 , a plasma generation process S20 (a part of the negative ion irradiation process), and a voltage application process S30 (a part of the negative ion irradiation process). Each process is executed by the control unit 50 . First, the gas supply control unit 51 of the control unit 50 controls the gas supply unit 40 to supply gas into the vacuum chamber 10 (gas supply process S10 ). Thereby, the gas of O ₂ exists in the generation chamber 10b of the vacuum chamber 10. Then, the plasma generation process S20 is performed. The plasma control unit 52 of the control unit 50 controls the plasma generation unit 14 to generate plasma P and electrons in the vacuum chamber 10 , and stops the generation of the plasma P to generate negative ions (electrons) from the electrons and gas. Slurry generation process S20). When the plasma P and electrons are generated in the generation chamber 10 b of the vacuum chamber 10 , the reaction of “O ₂ +e ⁻ →2O+e ⁻ ” proceeds by the plasma P. Then, when the generation of the plasma P is stopped, the electron temperature in the generation chamber 10b is rapidly lowered, and the reaction of “O+e ⁻ →O ⁻ ” proceeds. The voltage application process S30 is performed at a predetermined timing after the plasma generation process S20 is performed. Strictly speaking, negative ions are also generated during plasma generation, and when negative ions are irradiated, negative ions generated during plasma generation are also irradiated. The voltage control unit 53 of the control unit 50 controls the voltage application unit 90 and applies a bias voltage to the compound semiconductor 11 (voltage application process S30 ). Thereby, the negative ions 81 of O ⁻ in the generation chamber 10b are directed to the compound semiconductor 11 side, and are irradiated to the compound semiconductor 11 (see FIGS. 2 and 4 ). Next, the action and effect of the negative ion irradiation apparatus 1 and the control method thereof according to the present embodiment will be described. In the negative ion irradiation apparatus 1 of the present embodiment, the control unit 50 controls the gas supply unit 40 to supply the gas into the vacuum chamber 10 . The gas supply unit 40 supplies a gas containing the same element as the ions forming the compound semiconductor 11 . Therefore, the same element as the ions forming the compound semiconductor 11 exists in the vacuum chamber 10 . Furthermore, the control unit 50 generates the plasma P and electrons in the vacuum chamber 10 by controlling the plasma generating unit 14 , and stops the generation of the plasma P, generates negative ions from the electrons and the gas, and irradiates the negative ions with the negative ions. onto the compound semiconductor 11 . For example, as shown in FIG. 4( a ), the compound semiconductor 11 is irradiated with negative ions 81 of the same element as the ions forming the compound semiconductor 11 . The negative ions 81 enter the inside from the surface 11 a of the compound semiconductor 11 . Thereby, the negative ions 81 enter the crystal defects 85 derived from the anions in the compound semiconductor 11, and as shown in FIG. 4( b ), the crystal defects 85 can be filled. Here, the advantages of irradiating negative ions with respect to the compound semiconductor 11 will be described with reference to FIGS. 5 and 6 . In FIGS. 5 and 6 , the ionic bond structure of the cation 86 and the anion 87 forming the compound semiconductor 11 is shown. FIG. 5 is a diagram schematically showing the state when positive ions 83 are implanted into the compound semiconductor as a comparative example. As shown in FIG. 5 , when positive ions 83 are implanted into the compound semiconductor 11 , the positive ions 83 must pass under the influence of the Coulomb force of the cations 86 and the anions 87 , so that it is difficult to smoothly enter the compound semiconductor 11 . In addition, if electrons 82 as secondary electrons are released by the injection of positive ions 83 , there is a problem that the substrate is charged

On the other hand, when the negative ions 81 (refer to FIG. 6( a )) toward the compound semiconductor 11 reach the compound semiconductor 11 , as shown in FIG. 6( b ), the colliding electrons 82 are easily detached. Therefore, the negative ions 81 enter into the ionic bond as particles 81a from which the electrons 82 have been released from the neutral state. The particles 81 a in the neutral state are not affected by the Coulomb force of the cations 86 and the anions 87 , and can smoothly enter the compound semiconductor 11 . Therefore, the energy of the negative ions 81 can be as low as 70 eV or less, for example. In addition, when the negative ions 81 are implanted, the charging of the substrate does not occur. In addition, the negative ions 81 are implanted into the compound semiconductor 11 in a state heated by the heating unit 30 (see FIG. 1 ). Therefore, the desired element is diffused into the deep portion of the compound semiconductor 11 by concentration diffusion, and the excess element is removed by heat treatment, so that the particles 81a can fill only the crystal defects.

Further, for example, as a comparative example, when the negative ions are irradiated using the negative ion source, the area where the negative ions can be irradiated is small. On the other hand, as in the present embodiment, the negative ion irradiation apparatus 1 including the plasma generating unit 14 can irradiate the compound semiconductor 11 with negative ions over a large area.

In addition, for example, when only negative ions of a single energy are irradiated as a comparative example, the negative ions enter only a predetermined depth position of the compound semiconductor 11 , so that the crystal defects cannot be filled in a wide range in the depth direction. On the other hand, according to the negative ion irradiation apparatus 1 of this embodiment, since negative ions with a wide energy range can be generated, crystal defects can be filled in a wide range in the depth direction.

As described above, the negative ion irradiation apparatus 1 of the present embodiment can fill in the crystal defects of the compound semiconductor 11 , so that the quality of the compound semiconductor 11 can be improved. Also, before negative ion irradiation, even as a compound semiconductor Even when the grade of 11 is insufficient, the quality can be improved by negative ion irradiation, so that the need for preliminarily screening the grade of the single crystal substrate can be reduced. With the above, the production efficiency and quality of compound semiconductors can be improved.

The control method of the negative ion irradiation apparatus 1 of the present embodiment includes: a gas supply process S10, which controls the gas supply unit 40 to supply gas into the vacuum chamber 10; the negative ion irradiation process (plasma generation process S20, voltage application process S30), controls The plasma generation unit 14 generates plasma P and electrons in the vacuum chamber 10 , and stops the generation of the plasma P to generate negative ions from the electrons and gas, and irradiates the compound semiconductor 11 with the negative ions.

With the control method of the negative ion irradiation apparatus 1 of the present embodiment, the same functions and effects as those of the negative ion irradiation apparatus 1 described above can be obtained.

An embodiment of the present embodiment has been described above, but the present invention is not limited to the above-described embodiment, and can be modified or applied to other embodiments within the scope of not changing the gist described in the claims.

Moreover, in the said embodiment, the negative ion irradiation apparatus which also has a function as an ion-plating type film-forming apparatus was demonstrated, but the negative ion irradiation apparatus may not have the function of a film-forming apparatus. Therefore, the plasma P can be guided to, for example, an electrode or the like of a wall portion facing the plasma gun.

For example, in the above-described embodiment, the plasma gun 7 is a pressure gradient type plasma gun, but the plasma gun 7 is not limited to a pressure gradient type plasma gun as long as it can generate plasma in the vacuum chamber 10 . Plasma gun.

In the above-described embodiment, only one set of the plasma gun 7 and the position (heart mechanism 2) for guiding the plasma P is provided in the vacuum chamber 10, but a plurality of sets may be provided. In addition, plasma P may be supplied from a plurality of plasma guns 7 to one position.

1: Negative ion irradiation device (negative ion irradiation device) 3: Conveying mechanism (configuration department) 7: Plasma Gun 10: Vacuum chamber 11: Compound Semiconductors 14: Plasma generation part 40: Gas supply part 50: Control Department P: Plasma

FIG. 1 is a schematic cross-sectional view showing the configuration of a negative ion irradiation apparatus according to an embodiment of the present invention, and is a diagram showing an operating state at the time of plasma generation. FIG. 2 is a schematic cross-sectional view showing the configuration of the negative ion irradiation apparatus of FIG. 1 , and is a view showing an operating state when plasma is stopped. FIG. 3 is a flowchart showing a control method of the negative ion irradiation apparatus of the present embodiment. FIG. 4 is a diagram schematically showing a state when negative ions are irradiated to the compound semiconductor. FIG. 5 is a diagram schematically showing a state when positive ions are implanted into a compound semiconductor as a comparative example. FIG. 6 is a diagram schematically showing the state of implantation of negative ions into the compound semiconductor.

1: Negative ion irradiation device

2: Hearth mechanism

3: Conveying mechanism (configuration department)

5: steering coil

6: Ring Hearth

7: Plasma Gun

9: Coil

10: Vacuum chamber

10a: Delivery room

10b: Generation Chamber

10c: Plasma port

10h (10W): Sidewall

10i (10W): Sidewall

10j(10W): Bottom wall

11: Compound Semiconductors

12: Container

14: Plasma generation part

15: Conveying rollers

16: Compound semiconductor holding member

17: Main Hearth

17a: Filler

18(90): trolley wire

20: Permanent magnet part

27: Bias power supply

30: Heating part

34: Circuit Department

35(90): Bias circuit

40: Gas supply part

41: Gas supply port

42: Power supply brush

50: Control Department

51: Gas supply control section

52: Plasma Control Department

53: Voltage Control Department

60: Cathode

61: 1st intermediate electrode

61a: Ring permanent magnet

62: 2nd intermediate electrode

62a: Electromagnet coil

71: 1st wiring

72: 2nd wiring

73: 3rd wiring

80: Variable power

A: Arrow

P: Plasma

R1: Resistor

R2: Resistor

R3: Resistor

R4: Resistor

SW1: Short circuit switch

SW2: Short circuit switch

SW3: Short circuit switch

Claims (3)

A negative ion irradiation device for irradiating a compound semiconductor with negative ions, the negative ion irradiation device comprising: a chamber for generating the negative ions inside; a gas supply part for supplying a gas containing the same element as the ions forming the compound semiconductor; plasma a generating unit for generating plasma and electrons in the chamber; an arrangement unit for arranging the compound semiconductor; and a control unit for controlling the negative ion irradiation device, the control unit controlling the gas supply unit to supply the gas into the chamber, The control unit controls the plasma generating unit to generate the plasma and the electrons in the chamber, and stops the generation of the plasma to generate the negative ions from the electrons and the gas, and irradiates the negative ions to the compound semiconductor. The negative ion irradiation apparatus according to claim 1, further comprising: a voltage applying unit for applying a bias voltage to the compound semiconductor. A control method of a negative ion irradiation device for irradiating negative ions to a compound semiconductor, wherein the negative ion irradiation device comprises: a chamber in which the negative ions are generated; a gas supply unit for supplying a gas containing the same element as ions forming the compound semiconductor; a plasma generation unit for generating plasma and electrons in the chamber; an arrangement unit for arranging the compound semiconductor; and a control unit for performing the negative ion irradiation For the control of the device, the control method of the negative ion irradiation device includes: a gas supply process, in which the gas supply part is controlled by the control part to supply the gas into the chamber; and a negative ion irradiation process, the plasma is controlled by the control part. The generating unit generates the plasma and the electrons in the chamber, stops the generation of the plasma, generates the negative ions from the electrons and the gas, and irradiates the compound semiconductor with the negative ions.

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