CN212770941U

CN212770941U - Metal organic compound vapor deposition system

Info

Publication number: CN212770941U
Application number: CN202021390534.7U
Authority: CN
Inventors: 杨学林; 沈波; 沈剑飞; 刘丹烁; 蔡子东; 杨志坚; 王新强
Original assignee: Peking University
Current assignee: Peking University
Priority date: 2020-07-15
Filing date: 2020-07-15
Publication date: 2021-03-23
Anticipated expiration: 2030-07-15

Abstract

The utility model discloses a Metal Organic Compound Vapor Deposition (MOCVD) system, including the reacting chamber, carry the air supply, the tribal source, the five clan sources, the total pipeline in the tribal source, the total pipeline in the five clan sources and tail gas processing unit, its characterized in that, this MOCVD system still includes external carbon source, and the air supply passes through this external carbon source of tube coupling, and this external carbon source is again through the total pipeline in tube coupling three clan sources or lug connection reacting chamber to be equipped with mass flow controller on the pipeline of the total pipeline in external carbon source coupling three clan sources or reacting chamber. The MOCVD system can be used for carrying out GaN epitaxial growth under the optimal GaN growth condition, and the preparation of the semi-insulating high-resistance GaN material is realized by accurately regulating the concentration of C impurities in the GaN material by controlling the flow of the added carbon source while maintaining the high crystal quality of the GaN material.

Description

Metal organic compound vapor deposition system

Technical Field

The utility model belongs to the technical field of the semiconductor, especially, relate to a Metal Organic Chemical Vapor Deposition (MOCVD) system for preparing high resistant gallium nitride.

Background

Metal Organic Chemical Vapor Deposition (MOCVD), a vapor phase epitaxy technique for growing thin films by using the thermal decomposition reaction of metal organic compounds. MOCVD starts from the hetero-epitaxial growth of III-V group semiconductor materials on sapphire by Manasexit in 1968, has the characteristics of high control precision, good repeatability, easiness in batch production and the like through the development of nearly half a century, and develops into one of the most important epitaxial technologies in the fields of microelectronics and optoelectronics, including the field of semiconductor low dimension. MOCVD, an important component of modern epitaxy technology, has been expanded into a variety of material systems such as insulating media, metallic materials, and the like. In the production of a group iii-V compound semiconductor, its source materials are a saturated vapor of an organic compound containing a group iii metal element (an alkyl-type compound having an atomic group generally of a methyl group or an ethyl group) and a hydride of a group V element. The whole growth process involves a plurality of physical and chemical processes, and is a more complex working system.

The MOCVD system can be used for epitaxial growth of GaN-based power electronic devices in batch, and is often used in high-frequency, high-voltage and high-temperature working environments, and the voltage resistance and the leakage characteristics of the devices become one of the most important indexes of the GaN-based power electronic devices. The semi-insulating high-resistance GaN buffer layer can effectively isolate the substrate from the active region of the device, and plays an important role in reducing the electric leakage of the GaN-based power electronic device. In order to obtain a semi-insulating high-resistance GaN buffer layer through epitaxial growth and improve the performance of a device, a method of doping acceptor type impurity carbon (C) into a GaN material is generally adopted to compensate background n-type conductivity of the GaN material, so that semi-insulating high-resistance GaN is obtained. However, for conventional MOCVD systems, this can only be achieved by C-dopant in-situ doping techniques, such as [1] Hady Yacobub, et al, IEEE Trans Electron Devices 65,3192 (2018). This technique utilizes trimethylgallium (TMGa) as a precursor of Ga and C elements by changing growth conditions (e.g., low growth temperature and low growth pressure) during the epitaxial GaN process, and incorporates acceptor-type impurity C into the GaN material. However, this technique requires more extreme growth conditions to incorporate higher C impurity concentration, and such extreme growth conditions may cause the GaN material crystal quality to be degraded, and meanwhile, the instability of the growth conditions also causes great difficulty in precisely controlling the C impurity concentration.

SUMMERY OF THE UTILITY MODEL

In order to overcome the not enough of above-mentioned prior art, the utility model provides a Metal Organic Compound Vapor Deposition (MOCVD) system for preparation high resistant gallium nitride, on current MOCVD equipment basis promptly, increased additional carbon source all the way through equipment transformation, and in the GaN epitaxial growth in-process, let in additional carbon source in the reacting chamber, through controlling specific growth condition, prepare high-quality semi-insulating high resistant GaN film material.

Specifically, the technical scheme of the utility model as follows:

a Metal Organic Chemical Vapor Deposition (MOCVD) system comprises a reaction chamber, a carrier gas source, a group III source, a group V source, a group III source main pipeline, a group V source main pipeline and a tail gas treatment unit, wherein: the carrier gas source is respectively connected with the III-group source and the V-group source through pipelines, the compound of the III-group source is carried by the carrier gas to enter the III-group source main pipeline and then is conveyed to the reaction chamber, and the compound of the V-group source is carried by the carrier gas to enter the V-group source main pipeline and then is conveyed to the reaction chamber; the method is characterized in that the MOCVD system further comprises an external carbon source, the carrier gas source is connected with the external carbon source through a pipeline, and the external carbon source is connected with a main pipeline of a three-group source through a pipeline or directly connected with the reaction chamber; and a mass flow controller is arranged on a pipeline for connecting the external carbon source with the main pipeline of the three-family source or the reaction chamber.

In the MOCVD system of the utility model, an external carbon source can be connected into a main pipeline of the III-family source and transported to a reaction chamber through the main pipeline of the III-family source, and can also be directly connected into the reaction chamber; the flow of the external carbon source is controlled by a mass flow controller.

Adopt the utility model discloses a MOCVD system carries out the preparation of high-quality semi-insulating high resistant GaN film material, including following step:

(1) selecting a substrate to be placed in a reaction chamber, wherein the substrate can be any one of a silicon substrate, a silicon carbide substrate, a diamond substrate, a sapphire substrate and a III-V compound substrate;

(2) carrying reaction gas into a reaction chamber through carrier gas at a certain flow rate, conveying a III-family source compound into the reaction chamber through a III-family source main pipeline, and conveying a V-family source compound into the reaction chamber through a V-family source main pipeline, wherein the environment of the reaction chamber is set to be under high-temperature and low-pressure conditions;

(3) in the process, an external carbon source is introduced into the reaction chamber by carrying with carrier gas, and the flow of the external carbon source is controlled by a mass flow controller;

(4) and the carrier gas carries the compounds of the III-family source, the V-family source and the external carbon source to be transported to the reaction chamber and then mixed, the chemical reaction is carried out on the surface of the high-temperature substrate, the semi-insulating high-resistance GaN film is deposited on the substrate, and the by-product is discharged to the tail gas treatment unit.

The group iii source is preferably a trimethylgallium source, and is a device for supplying an organic compound (alkyl compound having an atomic group generally being a methyl group or an ethyl group) of a group iii metal element.

For the group V source, the group V source is a device for providing a hydride of a group V element, and the group V source is preferably an ammonia gas source.

For the carrier gas source, the carrier gas is typically nitrogen, hydrogen, or a mixture of both.

The carbon source is a device for supplying hydrocarbon, and the hydrocarbon is gaseous under the growth conditions of high temperature and low pressure, and is preferably hydrocarbon having 4 or less carbon atoms such as methane, acetylene, ethylene, ethane, propane, and the like.

The utility model discloses an among the MOCVD system, can insert into the main pipeline in third of the family source additional carbon source, transport the reaction chamber via the main pipeline in third of the family source, also can be with in the direct access reaction chamber of additional carbon source.

The utility model discloses a MOCVD system of uniquely plus carbon source through the outer carbon source flow of mass flow controller control, has overcome the difficult point of doping C impurity in the current semi-insulating high resistance GaN material, need not realize through the growth condition that changes GaN that semi-insulating high resistance GaN material dopes C impurity. In the GaN epitaxial process, GaN can be optimally grown under the optimal growth conditions, the flow of an external carbon source is regulated by a mass flow controller while the high crystal quality of the GaN material is maintained, and the carbon impurity concentration can be 1E 17cm^-3To 1.5E 19cm^-3And (4) accurately regulating and controlling. The utility model discloses it has very big practical application to utilize MOCVD system to carry out the industrialization production gaN base power electron device and worth.

Drawings

FIG. 1 is a schematic view of the MOCVD system employed in example 1;

FIG. 2 is a schematic view of the MOCVD system employed in example 2;

wherein, 1-carrier gas source; 2-a five-family source; 3-five family source main pipeline; 4-a group III source main pipeline; 5-a group III source; 6-additional carbon source; 7-mass flow controller; 8-a reaction chamber; 9-a substrate; 10-tail gas treatment unit.

Detailed Description

The present invention will be described in detail below by way of embodiments with reference to the accompanying drawings.

Example 1

As shown in fig. 1, the MOCVD system for preparing high-resistance gallium nitride in this embodiment includes a carrier gas source 1, a group-five source 2, a group-five source main pipeline 3, a group-iii source main pipeline 4, a group-iii source 5, an external carbon source 6, a mass flow controller 7, a reaction chamber 8, and a tail gas treatment unit 10, wherein: the carrier gas source 1 is respectively connected with a five-family source 2, a five-family source main pipeline 3, a three-family source 5, a three-family source main pipeline 4 and an external carbon source 6 through pipelines; the group-V source compound is carried by carrier gas, enters the group-V source main pipeline 3 and is conveyed to the reaction chamber 8; the III-group source compound is carried by carrier gas to enter a III-group source main pipeline 4 and then is conveyed to a reaction chamber 8; the hydrocarbon in the external carbon source 6 is carried by carrier gas, firstly enters the three-family source main pipeline 4 and then is conveyed to the reaction chamber 8; a mass flow controller 7 is arranged on a connecting pipeline from the external carbon source 6 to the three-group source main pipeline 4.

The method for preparing the semi-insulating high-resistance GaN film by using the MOCVD system comprises the following steps:

(1) a GaN substrate 9 is selected to be placed in the reaction chamber 8;

(2) hydrogen is taken as carrier gas to carry reaction gas into a reaction chamber 8, wherein the group five source adopts ammonia gas and is conveyed into the reaction chamber 8 through a group five source main pipeline 3, the group three source adopts trimethyl gallium and is conveyed into the reaction chamber 8 through a group three source main pipeline 4, the environment of the reaction chamber 8 is 900-1100 ℃, and the growth pressure is 10-300 mbar;

(3) the external carbon source 6 adopts propane, the hydrogen output by the carrier gas source 1 carries propane, and the propane enters the main pipeline 4 of the III-family source under the regulation and control flow of the mass flow controller 7 and finally enters the reaction chamber 8;

(4) the hydrogen carrying trimethyl gallium, ammonia gas and propane are transported to the reaction chamber 8 and then mixed, chemical reaction is carried out on the surface of the high-temperature GaN substrate 9, a semi-insulating high-resistance GaN film is deposited on the substrate, and the by-product is discharged to the tail gas treatment unit 10.

Example 2

As shown in fig. 2, the MOCVD system for preparing high-resistance gallium nitride in the present embodiment includes a carrier gas source 1, a group-five source 2, a group-five source main pipe 3, a group-iii source main pipe 4, a group-iii source 5, an external carbon source 6, a mass flow controller 7, a reaction chamber 8, and a tail gas treatment unit 10, wherein: the carrier gas source 1 is respectively connected with a five-family source 2, a five-family source main pipeline 3, a three-family source 5, a three-family source main pipeline 4 and an external carbon source 6 through pipelines; the group-V source compound is carried by carrier gas, enters the group-V source main pipeline 3 and is conveyed to the reaction chamber 8; the III-group source compound is carried by carrier gas to enter a III-group source main pipeline 4 and then is conveyed to a reaction chamber 8; the hydrocarbon in the external carbon source 6 is carried by the carrier gas and is directly conveyed to the reaction chamber 8 through a pipeline; a mass flow controller 7 is arranged on a connecting pipeline from the external carbon source 6 to the reaction chamber 8.

(1) a GaN substrate 9 is selected to be placed in the reaction chamber 8;

(3) the external carbon source 6 adopts ethylene, and the hydrogen output by the carrier gas source 1 carries the ethylene and directly enters the reaction chamber 8 under the regulation and control flow of the mass flow controller 7;

(4) the hydrogen carrying trimethyl gallium, ammonia gas and ethylene are transported to the reaction chamber 8 and then mixed, chemical reaction is carried out on the surface of the high-temperature GaN substrate 9, a semi-insulating high-resistance GaN film is deposited on the substrate, and the by-product is discharged to the tail gas treatment unit 10.

The above embodiments are merely illustrative of the technical ideas and features of the present invention, and the description thereof is specific and detailed, so as to enable one of ordinary skill in the art to understand the contents of the present invention and to implement the same, but the scope of the present invention is not limited thereto. It will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit of the invention, and it is intended to cover all such changes and modifications as fall within the true spirit of the invention.

Claims

1. A metal organic compound vapor deposition system comprises a reaction chamber, a carrier gas source, a three-family source, a five-family source, a three-family source main pipeline, a five-family source main pipeline and a tail gas treatment unit, wherein: the carrier gas source is respectively connected with the III-group source and the V-group source through pipelines, the compound of the III-group source is carried by the carrier gas to enter the III-group source main pipeline and then is conveyed to the reaction chamber, and the compound of the V-group source is carried by the carrier gas to enter the V-group source main pipeline and then is conveyed to the reaction chamber; the method is characterized in that the metal organic compound vapor deposition system further comprises an external carbon source, the carrier gas source is connected with the external carbon source through a pipeline, and the external carbon source is connected with a main pipeline of a three-group source through a pipeline or directly connected with the reaction chamber; and a mass flow controller is arranged on a pipeline for connecting the external carbon source with the main pipeline of the three-family source or the reaction chamber.

2. The metal organic vapor deposition system of claim 1, wherein the external carbon source is a hydrocarbon providing device.

3. The metal organic compound vapor deposition system according to claim 2, wherein the hydrocarbon is a hydrocarbon having 4 or less carbon atoms.

4. A metal organic compound vapor deposition system according to claim 3, wherein the hydrocarbon is methane, acetylene, ethylene, ethane and/or propane.

5. The metal organic vapor deposition system of claim 1, wherein the group three source is a trimethyl gallium source and the group five source is an ammonia source.