阅读说明：本技术 一种用于磷化铟单晶vgf工艺的压力控制系统及工艺 (Pressure control system and process for indium phosphide single crystal VGF (vacuum vapor deposition) process ) 是由 罗福敏 胡昌勇 李勇 刘留 苏小平 于 2020-07-22 设计创作，主要内容包括：本发明公开了一种用于磷化铟单晶VGF工艺的压力控制系统及工艺,涉及半导体材料制备技术领域。本发明的一种用于磷化铟单晶VGF工艺的压力控制系统及工艺,包括单晶炉、真空泵以及压缩氮气瓶,还包括五通球阀,所述单晶炉、真空泵、压缩氮气瓶均与五通球阀通过管道相连通,所述五通球阀和压缩氮气瓶之间的管道上还安装有两个减压阀。本发明公开了一种用于磷化铟单晶VGF工艺的压力控制系统及工艺,能够有效的控制磷化铟单晶生产过程中单晶炉内的压力稳定,避免炸管,从而提高了生产效率,且在一定程度上降低了生产成本。(The invention discloses a pressure control system and process for an indium phosphide single-crystal VGF (vacuum vapor deposition) process, and relates to the technical field of semiconductor material preparation. The pressure control system and process for the VGF process for the indium phosphide single crystal comprise a single crystal furnace, a vacuum pump, a compressed nitrogen cylinder and a five-way ball valve, wherein the single crystal furnace, the vacuum pump and the compressed nitrogen cylinder are all communicated with the five-way ball valve through pipelines, and two reducing valves are further arranged on the pipeline between the five-way ball valve and the compressed nitrogen cylinder. The invention discloses a pressure control system and a pressure control process for an indium phosphide single-crystal VGF (vacuum vapor deposition) process, which can effectively control the pressure in a single-crystal furnace to be stable in the production process of an indium phosphide single-crystal and avoid tube explosion, thereby improving the production efficiency and reducing the production cost to a certain extent.)

1. The pressure control system for the VGF process of the indium phosphide single crystal comprises a single crystal furnace, a vacuum pump and a compressed nitrogen cylinder and is characterized by further comprising a five-way ball valve, wherein the single crystal furnace, the vacuum pump and the compressed nitrogen cylinder are communicated with the five-way ball valve through pipelines, and two pressure reducing valves are further mounted on the pipeline between the five-way ball valve and the compressed nitrogen cylinder.

2. The pressure control system of claim 1, wherein a one-way valve is further installed between the two pressure reducing valves.

3. The pressure control system of claim 2, wherein the pressure reducing valve comprises a first pressure reducing valve and a second pressure reducing valve, and a needle valve is further mounted between the one-way valve and the second pressure reducing valve.

4. The pressure control system for the VGF process of an indium phosphide single crystal as set forth in claim 1, wherein a digital display barometer is installed on a pipeline between the single crystal furnace and the five-way ball valve, and the digital display barometer is located close to the single crystal furnace.

5. The pressure control system of claim 1, wherein a vent line is further connected to the five-way ball valve.

6. The pressure control system of claim 1, wherein air pressure gauges are mounted on the pipeline at positions close to the air outlet ends of the first pressure reducing valve and the second pressure reducing valve.

7. A pressure control process for VGF (vertical vapor deposition) process of an indium phosphide single crystal, which is characterized by using the control system as claimed in any one of claims 1 to 6, and comprises the following steps:

s1: putting the quartz crucible which is welded and packaged into a single crystal furnace;

s2: closing the five-way ball valve, opening and adjusting the first pressure reducing valve and the second pressure reducing valve until the reading of the barometer at the air outlet end of the first pressure reducing valve is 400-;

s3: the single crystal furnace starts to be heated, the five-way ball valve is rotated at the same time, the single crystal furnace is communicated with the vacuum pump, and the vacuum pump is started to vacuumize the single crystal furnace;

s4: detecting the vacuum degree in the single crystal furnace by a digital display gas pressure gauge until the vacuum degree in the single crystal furnace reaches less than 10^-3And the temperature is higher than 400 ℃, the temperature rising speed is controlled to be 2.0-4.0 ℃/min, a five-way ball valve is rotated, the single crystal furnace is communicated with the nitrogen compression bottle, and the vacuum pump is closed;

s5: adjusting a needle valve, controlling the rising speed of the air pressure in the single crystal furnace to ensure that the reading of a digital display barometer reaches 290-310PSI within 30-50min, and then rotating a five-way ball valve to a blind end;

s6: continuously raising the temperature in the single crystal furnace 1 to 1000-420 PSI (pressure gradient) and 1100 ℃ until the temperature in the single crystal furnace tends to be constant, rotating the five-way ball valve to communicate the single crystal furnace with the nitrogen compression bottle, and controlling the reading of the digital display barometer to 400-420PSI after the air pressure in the single crystal furnace is stable;

s7: and (3) after the growth of the single crystal is finished, rotating the five-way ball valve to communicate the single crystal furnace with the emptying pipeline, completely discharging nitrogen in the single crystal furnace within 90-120min, and taking out the grown quartz crucible when the reading of a digital display barometer is 0.

8. The pressure control process for VGF (vacuum gas pressure control) process for an indium phosphide single crystal as a single crystal of claim 7, wherein the step S6 is carried out by the following steps: if the reading of the digital display barometer is lower than 400PSI, increasing the pressure of the air outlet end of the first pressure reducing valve; if the reading is higher than 420PSI, the five-way ball valve is rotated to communicate the single crystal furnace with the emptying pipeline, and the nitrogen in the single crystal furnace is partially discharged.

Technical Field

The invention relates to the technical field of semiconductor material preparation, in particular to a pressure control system and process for an indium phosphide single-crystal VGF (vacuum gas plasma) process.

Background

Indium phosphide (InP) is an important compound semiconductor material, and has higher photoelectric conversion efficiency, high electron mobility, high operating temperature, and strong radiation resistance compared to silicon and gallium arsenide, and has important applications in the fields of optical communication, millimeter wave high frequency, low noise, broadband microelectronic integration, and the like.

The preparation method of the indium phosphide single crystal is commonly used in the market by a high-pressure liquid-sealed Czochralski method (LEC) and a vertical temperature gradient solidification method (VGF), wherein the VGF has the advantages of other methods, and has the biggest characteristics of low temperature gradient during growth, slow growth speed and easy obtainment of III-V group compound semiconductor crystals with low dislocation density. When the VGF process is used for growing the indium phosphide single crystal, firstly, the indium phosphide polycrystal material is cleaned, and then is put into a cleaned PBN crucible together with a doping agent, a B2O3 liquid sealing agent, high-purity red phosphorus, seed crystals and the like, and then the cleaned PBN crucible is put into a quartz crucible. Then, the inside of the quartz crucible was evacuated using a molecular vacuum pump, and the evacuated quartz crucible was sealed with an oxyhydrogen flame. When indium phosphide single crystal growth is carried out, high-purity red phosphorus charged during batching is sublimated into red phosphorus vapor along with temperature rise, and pressure of 2.5-3.0MPa is generated in the quartz crucible. The quartz crucible bears the pressure of 2.5-3.0Mpa, so that a burst tube (the quartz crucible is broken and red phosphorus is leaked and burned) is easily caused, phosphorus-containing substances such as red phosphorus, phosphorus pentoxide and the like are adhered to the inside of the single crystal furnace after red phosphorus of the burst tube is leaked and burned, the S-shaped platinum-rhodium wire for temperature control and temperature measurement can be corroded at high temperature, the S-shaped platinum-rhodium wire is broken, the production cannot be continued, the single crystal furnace after the burst tube needs to be dismantled and manufactured again, and the loss of the burst tube is about 10912.55 yuan each time.

Therefore, during production, gas must be filled in the quartz crucible to balance the pressure in the quartz crucible, meanwhile, in order to ensure the quality of the growing single crystal, the filled gas must be high-purity (more than or equal to 5N), and before filling, the air in the single crystal furnace must be pumped away to keep a vacuum state. However, the existing pressure control system often has the problem that the pressure of gas in the single crystal furnace cannot be effectively controlled, so that the pressure in the single crystal furnace is unstable, and further the quartz crucible is broken.

Disclosure of Invention

In view of the above problems, the present invention aims to disclose a pressure control system and process for a VGF process of indium phosphide single crystal, which can effectively control the pressure in a single crystal furnace to be stable during the production process of indium phosphide single crystal, and avoid tube explosion, thereby improving the production efficiency and reducing the production cost to a certain extent.

The pressure control system for the VGF process of the indium phosphide single crystal comprises a single crystal furnace, a vacuum pump, a compressed nitrogen cylinder and a five-way ball valve, wherein the single crystal furnace, the vacuum pump and the compressed nitrogen cylinder are all communicated with the five-way ball valve through pipelines, and two reducing valves are further arranged on the pipeline between the five-way ball valve and the compressed nitrogen cylinder.

Further, a check valve is further installed between the two pressure reducing valves.

Further, the pressure reducing valve comprises a first pressure reducing valve and a second pressure reducing valve, and a needle valve is further installed between the one-way valve and the second pressure reducing valve.

Further, a digital display barometer is arranged on a pipeline between the single crystal furnace and the five-way ball valve and is positioned close to the single crystal furnace.

Further, an emptying pipeline is connected to the five-way ball valve.

Further, barometers are installed at positions, close to the air outlet ends of the first pressure reducing valve and the second pressure reducing valve, on the pipeline.

In addition, the invention also discloses a pressure control process for the VGF process of the indium phosphide single crystal, which uses the control system and specifically comprises the following steps:

s1: putting the quartz crucible which is welded and packaged into a single crystal furnace;

s2: closing the five-way ball valve, opening and adjusting the first pressure reducing valve and the second pressure reducing valve until the reading of the barometer at the air outlet end of the first pressure reducing valve is 400-;

s3: the single crystal furnace starts to be heated, the five-way ball valve is rotated at the same time, the single crystal furnace is communicated with the vacuum pump, and the vacuum pump is started to vacuumize the single crystal furnace;

s4: detecting the vacuum degree in the single crystal furnace by a digital display gas pressure gauge until the vacuum degree in the single crystal furnace reaches less than 10^-3And a temperature of more than 40Controlling the heating speed to be 2.0-4.0 ℃/min at 0 ℃, rotating the five-way ball valve, communicating the single crystal furnace with the nitrogen compression bottle, and closing the vacuum pump;

s5: adjusting a needle valve, controlling the rising speed of the air pressure in the single crystal furnace to ensure that the reading of a digital display barometer reaches 290-310PSI within 30-50min, and then rotating a five-way ball valve to a blind end;

s6: continuously raising the temperature in the single crystal furnace 1 to 1000-420 PSI (pressure gradient) and 1100 ℃ until the temperature in the single crystal furnace tends to be constant, rotating the five-way ball valve to communicate the single crystal furnace with the nitrogen compression bottle, and controlling the reading of the digital display barometer to 400-420PSI after the air pressure in the single crystal furnace is stable;

s7: and (3) after the growth of the single crystal is finished, rotating the five-way ball valve to communicate the single crystal furnace with the emptying pipeline, completely discharging nitrogen in the single crystal furnace within 90-120min, and taking out the grown quartz crucible when the reading of a digital display barometer is 0.

Further, the step S6 is specifically performed to control the pressure inside the single crystal furnace: if the reading of the digital display barometer is lower than 400PSI, increasing the pressure of the air outlet end of the first pressure reducing valve; if the reading is higher than 420PSI, the five-way ball valve is rotated to communicate the single crystal furnace with the emptying pipeline, and the nitrogen in the single crystal furnace is partially discharged.

The invention has the beneficial effects that:

the invention discloses a pressure control system and a pressure control process for an indium phosphide single-crystal VGF (vacuum vapor deposition) process, which are simple and reasonable in structure arrangement, can effectively control the pressure in a single-crystal furnace to be stable in the production process of an indium phosphide single-crystal, and avoid tube explosion, thereby improving the production efficiency and reducing the production cost to a certain extent.

Drawings

FIG. 1 is a schematic diagram of a pressure control system for VGF process of single crystal indium phosphide (InP) according to the invention;

wherein, the single crystal furnace 1, the vacuum pump 2, the compressed nitrogen cylinder 3, the five-way ball valve 4, the emptying pipeline 5, the first pressure reducing valve 6, the second pressure reducing valve 7, the one-way valve 8, the needle valve 9, the digital display barometer 10 and the barometer 11

Detailed Description

The present invention will be described in detail with reference to specific examples below:

the invention relates to a pressure control system for an indium phosphide single crystal VGF process, which comprises a single crystal furnace 1, a vacuum pump 2, a compressed nitrogen cylinder 3 and a five-way ball valve 4, wherein the single crystal furnace 1, the vacuum pump 2 and the compressed nitrogen cylinder 3 are all communicated with the five-way ball valve 4 through pipelines, specifically, the five-way ball valve 4 comprises A, B, C, D, E five interfaces, wherein the single crystal furnace 1 is communicated with an interface E, the vacuum pump 2 is communicated with an interface D, the compressed nitrogen cylinder 3 is communicated with an interface B, the interface C is a sealed blind end, the interface A is communicated with an emptying pipeline 5, two pressure reducing valves are further arranged on the pipeline between the five-way ball valve 4 and the compressed nitrogen cylinder 3, each pressure reducing valve comprises a first pressure reducing valve 6 and a second pressure reducing valve 7, the pressure of nitrogen in the nitrogen compression cylinder can be reduced before entering the single crystal furnace 1 through the pressure reducing valves, more conveniently to the pressure in the control single crystal growing furnace 1, prevent the pressure increase suddenly, lead to single crystal growing furnace 1 to explode the pipe, still install check valve 8 between first relief pressure valve 6 and the second relief pressure valve 7, still install needle valve 9 between check valve 8 and the second relief pressure valve 7, the needle valve 9 of this embodiment is the high accuracy needle valve, the pressure in the control single crystal growing furnace 1 that can be more accurate, install digital display barometer 10 on the pipeline between single crystal growing furnace 1 and five-way ball valve 4, digital display barometer 10 is located the position that is close to single crystal growing furnace 1, can more directly perceived pressure in the single crystal growing furnace 1 monitors, barometer 11 is all installed to the position that is close to the end of giving vent to anger of first relief pressure valve 6 and second relief pressure valve 7 on the pipeline, can directly perceived pressure behind the relief pressure valve through barometer 11 nitrogen gas, it is more convenient to adjust the nitrogen gas pressure.

The pressure control of the VGF process of the indium phosphide single crystal by using the control system of the invention specifically comprises the following steps:

s1: putting the quartz crucible which is welded and packaged into a single crystal furnace;

s2: closing the five-way ball valve 4, opening and adjusting the first pressure reducing valve 6 and the second pressure reducing valve 7 until the barometer 11 at the air outlet end of the first pressure reducing valve 6 reads 400 and 420PSI, and the barometer 11 at the air outlet end of the second pressure reducing valve 7 reads 600 PSI;

s3: heating the single crystal furnace 1, rotating the five-way ball valve 4 to a port D, communicating the single crystal furnace 1 with the vacuum pump 2, and starting the vacuum pump 2 to vacuumize the single crystal furnace 1;

s4: detecting the vacuum degree in the single crystal furnace 1 through a digital display barometer 10 until the vacuum degree in the single crystal furnace 1 reaches less than 10^-3And the temperature is higher than 400 ℃, the temperature rising speed is controlled to be 2.0-4.0 ℃/min, the five-way ball valve 4 is rotated to be switched from the interface C to the interface B, and the vacuum pump 2 is closed;

s5: adjusting the needle valve 9, controlling the air pressure rising speed in the single crystal furnace 1 to ensure that the reading of the digital display barometer 10 reaches 290-;

s6: the temperature in the single crystal furnace 1 rises to 1100 ℃ plus 1000 ℃ until the temperature in the single crystal furnace 1 tends to be constant, the five-way ball valve 4 is switched from the interface C to the interface B, the reading of the digital display barometer 10 is controlled at 420PSI plus 400 after the air pressure in the single crystal furnace 1 is stable, and if the reading of the digital display barometer 10 is lower than 400PSI, the pressure at the air outlet end of the first pressure reducing valve 6 is increased; if the reading is higher than 420PSI, the five-way ball valve 44 is directly switched from the interface B to the interface A, and the nitrogen in the single crystal furnace 1 is partially discharged;

s7: and (3) cooling until the growth of the single crystal is finished, slowly turning the five-way ball valve 4 to the interface A when the temperature is reduced to 400 ℃, completely discharging nitrogen in the single crystal furnace 1 within 90-120min, and taking out the grown quartz crucible when the reading of a digital display barometer 10 is 0.

Compared with the traditional process, the control system and the process are used for the VGF process of the indium phosphide single crystal, the tube cracking rate of the traditional process is about 10 percent, 107 tubes are produced by adopting the new process, the tube cracking rate is 0, 1000 tubes are produced in full production per year, the cost is saved by about 100 ten thousand per year, and meanwhile, the manufacturing and debugging of a new single crystal furnace after tube cracking need more than 7 days.

Although the present invention has been described in detail with reference to the preferred embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted without departing from the spirit and scope of the invention as defined in the appended claims. The techniques, shapes, and configurations not described in detail in the present invention are all known techniques.