阅读说明：本技术 一种高纯大尺寸sic晶体衬底材料的制备方法 (Preparation method of high-purity large-size SIC crystal substrate material ) 是由 陈宇 严丽红 辛藤 于 2020-12-24 设计创作，主要内容包括：本发明适用于半导体技术领域,提供了一种高纯大尺寸SIC晶体衬底材料的制备方法,包括以下步骤：S1、按一定化学计量比称量硅粉和碳粉,将它们混合均匀后加入到石墨坩埚中；S2、在S1中的石墨坩埚中添加含有氯元素的先驱体并搅拌均匀；S3、将S2中的石墨坩埚放入真空烧结炉中后关炉,待真空抽至≤10～(-4)Pa以后,再充入稀有气体至所需压强；S4、按一定升温速率进行升温至所需温度进行高温合成,待一段时间后降温后,停炉取出样品。本发明通过添加含氯元素的先驱体,实现厚膜外延材料,单层外延层厚度达80微米,突破厚膜生长的重复性、稳定性、一致性等产业化瓶颈共性技术,并且消除硅滴以及硅组分失配等外延缺陷。(The invention is suitable for the technical field of semiconductors, and provides a preparation method of a high-purity large-size SIC crystal substrate material, which comprises the following steps: s1, weighing silicon powder and carbon powder according to a certain stoichiometric ratio, mixing the silicon powder and the carbon powder uniformly, and adding the mixture into a graphite crucible; s2, adding a precursor containing chlorine into the graphite crucible in the S1, and uniformly stirring; s3, putting the graphite crucible in the S2 into a vacuum sintering furnace, closing the furnace, and vacuumizing to be less than or equal to 10 DEG ‑4 After Pa, filling rare gas to the required pressure; and S4, heating to the required temperature according to a certain heating rate for high-temperature synthesis, cooling after a period of time, and stopping the furnace to take out the sample. According to the invention, the chlorine-containing precursor is added to realize a thick film epitaxial material, the thickness of a single-layer epitaxial layer reaches 80 microns, the common technology of industrialization bottlenecks such as repeatability, stability and consistency of thick film growth is broken through, and epitaxial defects such as silicon drops and silicon component mismatch are eliminated.)

1. A preparation method of a high-purity large-size SIC crystal substrate material is characterized by comprising the following steps:

s1, weighing silicon powder and carbon powder according to a certain stoichiometric ratio, mixing the silicon powder and the carbon powder uniformly, and adding the mixture into a graphite crucible;

s2, adding a precursor containing chlorine into the graphite crucible in the S1, and uniformly stirring;

s3, putting the graphite crucible in the S2 into a vacuum sintering furnace, closing the furnace, and vacuumizing to be less than or equal to 10 DEG^-4After Pa, filling rare gas to the required pressure;

and S4, heating to the required temperature according to a certain heating rate for high-temperature synthesis, cooling after a period of time, and stopping the furnace to take out the sample.

2. The method for preparing a high-purity large-size SIC crystal substrate material as claimed in claim 1, wherein the purity of both the silicon powder and the carbon powder in S1 is not less than 5N.

3. The method for preparing a high-purity large-size SIC crystal substrate material as claimed in claim 2, wherein the filling flow rate of the rare gas in S3 is 5-50 mL/min, and the filling time is 5-50 min.

4. The method for preparing a high purity large size SIC crystal substrate material as claimed in claim 1, wherein the rare gas in S3 is Ar gas.

5. The method for preparing a high purity large size SIC crystal substrate material as claimed in claim 4, wherein the ratio of silicon powder to carbon powder in S1 is 1: 1.

6. The method for preparing a high purity large size SIC crystal substrate material as claimed in claim 5, wherein the high temperature synthesis temperature in S4 is set to 1500-2500 ℃.

7. The method for preparing a high purity large size SIC crystal substrate material as claimed in claim 6, wherein the period of time in S4 is set to 5-15 h.

8. The method for preparing a high purity large size SIC crystal substrate material as claimed in claim 7, wherein the required pressure in S3 is set to 100to 800 Toor.

9. The method for preparing a high purity large size SIC crystal substrate material as claimed in claim 6, further comprising the step of testing and analyzing the sample in S4.

Technical Field

The invention belongs to the technical field of semiconductors, and particularly relates to a preparation method of a high-purity large-size SIC crystal substrate material.

Background

The SIC crystal substrate material is an important material which is indispensable for supporting the development of the power electronic industry. The high-voltage-resistant and high-frequency-resistant composite material has outstanding physical characteristics of high voltage resistance, high frequency resistance and the like, can be widely applied to the fields of high-power high-frequency electronic devices, PCUs (power control units) of electric vehicles, photovoltaic inverters, rail transit power control systems and the like, and plays roles in reducing the size, simplifying the system and improving the power density.

The SIC crystal substrate material as the target product of the project is mainly applied to high-capacity low-loss power devices, high-frequency high-speed devices, power devices used in special environments and optical microelectronic devices. Currently manufactured by the Lely method, the international mainstream products are transitioning from 4 inches to 6 inches, and 8-inch conductive substrate products have been developed.

The domestic substrate is mainly 4 inches, the quality is relatively weak, the method is mainly used for producing low-current products of below 10A, and the slow growth and unstable quality purity of the existing single crystal are important reasons of high price and slow market popularization of silicon carbide.

Disclosure of Invention

The invention provides a preparation method of a high-purity large-size SIC crystal substrate material, and aims to solve the problems that in the background technology, domestic substrates are mainly 4 inches, the quality is relatively weak, the substrate is mainly used for producing low-current products below 10A, and the existing single crystal grows slowly, the quality and purity are not stable enough, and the silicon carbide is high in price and slow in market popularization.

The invention is realized in such a way that a preparation method of a high-purity large-size SIC crystal substrate material comprises the following steps:

s1, weighing silicon powder and carbon powder according to a certain stoichiometric ratio, mixing the silicon powder and the carbon powder uniformly, and adding the mixture into a graphite crucible;

s2, adding a precursor containing chlorine into the graphite crucible in the S1, and uniformly stirring;

s3, putting the graphite crucible in the S2 into a vacuum sintering furnace, closing the furnace, and vacuumizing to be less than or equal to 10 DEG^-4After Pa, filling rare gas to the required pressure;

and S4, heating to the required temperature according to a certain heating rate for high-temperature synthesis, cooling after a period of time, and stopping the furnace to take out the sample.

Preferably, the purity of the silicon powder and the purity of the carbon powder in S1 are both more than or equal to 5N.

Preferably, the filling flow rate of the rare gas in the S3 is 5-50 mL/min, and the filling time is 5-50 min.

Preferably, the rare gas in S3 is Ar gas.

Preferably, the ratio of the silicon powder to the carbon powder in the S1 is 1: 1.

Preferably, the temperature during the high-temperature synthesis in S4 is set to 1500-2500 ℃.

Preferably, the period of time in S4 is set to 5-15 h.

Preferably, the required pressure in S3 is set to 100to 800 Toor.

Preferably, the method further comprises a step of testing and analyzing the sample in S4.

Compared with the prior art, the invention has the beneficial effects that: by adding the precursor containing chlorine elements, the thick-film epitaxial material is realized, the thickness of a single-layer epitaxial layer reaches 80 micrometers, the common technology of industrial bottlenecks of repeatability, stability, consistency and the like of thick-film growth is broken through, and the high-quality 6-inch silicon carbide epitaxial material is obtained. And the epitaxial defects of silicon drop, silicon component mismatch and the like are eliminated, and the requirements that the surface brightness, the thickness and the carrier concentration reach the preset target are grown.

Drawings

FIG. 1 is a schematic flow chart of the preparation method of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

Referring to fig. 1, the present invention provides a technical solution: a preparation method of a high-purity large-size SIC crystal substrate material comprises the following steps:

s1, weighing silicon powder and carbon powder according to a certain stoichiometric ratio, mixing the silicon powder and the carbon powder uniformly, and adding the mixture into a graphite crucible;

s2, adding a precursor containing chlorine into the graphite crucible in the S1, and uniformly stirring;

s3, putting the graphite crucible in the S2 into a vacuum sintering furnace, closing the furnace, and vacuumizingTo less than or equal to 10^-4After Pa, filling rare gas to the required pressure;

and S4, heating to the required temperature according to a certain heating rate for high-temperature synthesis, cooling after a period of time, and stopping the furnace to take out the sample.

In the invention, a precursor containing chlorine is added to realize a thick film epitaxial material, the thickness of a single-layer epitaxial layer reaches 80 microns, the doping concentration range is 1015-1019cm, and the surface macroscopic defect density is less than 8 cm-2. In the aspect of SiC epitaxial growth technology development, the common CVD method in the industry is used for epitaxial undoped active layers, and the thickness is only 20 microns or more. The invention breaks through the common industrialized bottleneck technologies of repeatability, stability, consistency and the like of thick film growth and obtains the high-quality 6-inch silicon carbide epitaxial material. Zoning control techniques have been developed. By adopting the sectional control of the Si vapor pressure of the growth chamber and the interface reaction front edge, the SI vapor pressure of the interface front edge is larger than that of the growth chamber, the epitaxial rate is ensured to be far larger than the decomposition rate, the SiC component at the interface front edge is proper, the epitaxial defects of silicon drop, silicon component mismatch and the like are eliminated, and the requirements of surface brightness, thickness and carrier concentration reaching the preset target are generated.

The purity of the silicon powder and the purity of the carbon powder in the S1 are both more than or equal to 5N.

In the present invention, the purity of the silicon powder and the purity of the carbon powder are preferably both 5N and 6N, or the purity of the silicon powder is 5N, the purity of the carbon powder is 6N, or the purity of the silicon powder is 6N, and the purity of the carbon powder is 5N.

The filling flow rate of the rare gas in the S3 is 5-50 mL/min, and the filling time is 5-50 min.

In the invention, the filling flow of the rare gas is preferably 10-40 mL/min, and more preferably 20-30 mL/min; the charging time is preferably 10 to 40min, and more preferably 20 to 30 min.

The rare gas in S3 is Ar gas.

In the present invention, argon is a colorless, odorless, monatomic gas with a relative atomic mass of 39.948. Argon gas is generally produced by a fractionation method after being liquefied by air. The density of argon is 1.4 times that of air and 10 times that of helium. Argon is an inert gas, does not react with other substances at normal temperature, and is not dissolved in liquid metal at high temperature.

The ratio of the silicon powder to the carbon powder in the S1 is 1: 1.

The temperature during high-temperature synthesis in S4 is set to 1500-2500 ℃.

In the invention, the temperature during high-temperature synthesis is preferably 1800-2200 ℃, and more preferably 2000 ℃.

The period of time in S4 is set to be 5-15 h.

In the invention, the period of time is preferably 6-12 h.

The required pressure in S3 is set to 100-800 Toor.

In the invention, the required pressure is preferably 200-600 Toor.

Also includes the step of testing and analyzing the sample in S4.

In the present invention, XRD diffraction data of the powder was collected at room temperature with a scan step of 0.02 ° and a scan rate of 1sec/step using a Bruker D8 ADVANCE X ray diffractometer as the X-ray source. The SEM image of the powder was measured using a SUI510 scanning electron microscope manufactured by HITACHI corporation. The median particle diameter (D50) of the powder was determined using a SICAS-4800 light-transmitting particle size distribution analyzer. The bulk density of the powder is determined by dividing the mass of the powder by the volume of the container occupied by the powder. The impurity element analysis of the powder was directly measured by a Glow Discharge Mass Spectrometer (GDMS) instrument VC 9000.

In order to further illustrate the present invention, the following detailed description is made on a high strength magnesium alloy material and a preparation method thereof, which are provided by the present invention, with reference to examples, but the present invention should not be construed as limiting the scope of the present invention.

Example 1

A preparation method of a high-purity large-size SIC crystal substrate material comprises the following steps:

s1, weighing silicon powder and carbon powder according to a certain stoichiometric ratio, mixing the silicon powder and the carbon powder uniformly, and adding the mixture into a graphite crucible; wherein, the purity of the silicon powder and the carbon powder is 5N.

S2, adding a precursor containing chlorine into the graphite crucible in the S1, and uniformly stirring;

S3、putting the graphite crucible in the S2 into a vacuum sintering furnace, closing the furnace, and vacuumizing to be less than or equal to 10 DEG^-4After Pa, filling rare gas to the required pressure; the filling flow of the rare gas is 5mL/min, the filling time is 5min, the rare gas is Ar gas, and the required pressure is set to be 100 Toor.

And S4, heating to the required temperature according to a certain heating rate for high-temperature synthesis, cooling after 5 hours, and stopping the furnace to take out the sample.

Example 2

A preparation method of a high-purity large-size SIC crystal substrate material comprises the following steps:

s1, weighing silicon powder and carbon powder according to a certain stoichiometric ratio, mixing the silicon powder and the carbon powder uniformly, and adding the mixture into a graphite crucible; wherein, the purity of the silicon powder and the carbon powder is 6N.

S2, adding a precursor containing chlorine into the graphite crucible in the S1, and uniformly stirring;

s3, putting the graphite crucible in the S2 into a vacuum sintering furnace, closing the furnace, and vacuumizing to be less than or equal to 10 DEG^-4After Pa, filling rare gas to the required pressure; the filling flow of the rare gas is 10mL/min, the filling time is 10min, the rare gas is Ar gas, and the required pressure is set to be 200 Toor.

And S4, heating to the required temperature according to a certain heating rate for high-temperature synthesis, cooling after 5 hours, and stopping the furnace to take out the sample.

Example 3

A preparation method of a high-purity large-size SIC crystal substrate material comprises the following steps:

s1, weighing silicon powder and carbon powder according to a certain stoichiometric ratio, mixing the silicon powder and the carbon powder uniformly, and adding the mixture into a graphite crucible; wherein, the purity of the silicon powder and the carbon powder is 5N.

S2, adding a precursor containing chlorine into the graphite crucible in the S1, and uniformly stirring;

s3, putting the graphite crucible in the S2 into a vacuum sintering furnace, closing the furnace, and vacuumizing to 10 DEG^-4After Pa, filling rare gas to the required pressure; the filling flow rate of the rare gas is 5mL/min, the filling time is 5min, the rare gas is neon,the desired pressure is set to 100 Toor.

And S4, heating to the required temperature according to a certain heating rate for high-temperature synthesis, cooling after 5 hours, and stopping the furnace to take out the sample.

Example 4

A preparation method of a high-purity large-size SIC crystal substrate material comprises the following steps:

s1, weighing silicon powder and carbon powder according to a certain stoichiometric ratio, mixing the silicon powder and the carbon powder uniformly, and adding the mixture into a graphite crucible; wherein, the purity of the silicon powder and the carbon powder is 6N.

S2, adding a precursor containing chlorine into the graphite crucible in the S1, and uniformly stirring;

s3, putting the graphite crucible in the S2 into a vacuum sintering furnace, closing the furnace, and vacuumizing to be less than or equal to 10 DEG^-4After Pa, filling rare gas to the required pressure; the filling flow of the rare gas is 20mL/min, the filling time is 20min, the rare gas is Ar gas, and the required pressure is set to be 400 Toor.

And S4, heating to the required temperature according to a certain heating rate for high-temperature synthesis, cooling after 10 hours, and stopping the furnace to take out the sample.

Example 5

A preparation method of a high-purity large-size SIC crystal substrate material comprises the following steps:

s1, weighing silicon powder and carbon powder according to a certain stoichiometric ratio, mixing the silicon powder and the carbon powder uniformly, and adding the mixture into a graphite crucible; wherein, the purity of the silicon powder and the carbon powder is 5N.

S2, adding a precursor containing chlorine into the graphite crucible in the S1, and uniformly stirring;

s3, putting the graphite crucible in the S2 into a vacuum sintering furnace, closing the furnace, and vacuumizing to be less than or equal to 10 DEG^-5After Pa, filling rare gas to the required pressure; the filling flow of the rare gas is 5-50 mL/min, the filling time is 30min, the rare gas is Ar gas, and the required pressure is set to be 600 Toor.

And S4, heating to the required temperature according to a certain heating rate for high-temperature synthesis, cooling after 15 hours, and stopping the furnace to take out the sample.

Example 6

A preparation method of a high-purity large-size SIC crystal substrate material comprises the following steps:

s1, weighing silicon powder and carbon powder according to a certain stoichiometric ratio, mixing the silicon powder and the carbon powder uniformly, and adding the mixture into a graphite crucible; wherein, the purity of the silicon powder and the carbon powder is 5N.

S2, adding a precursor containing chlorine into the graphite crucible in the S1, and uniformly stirring;

s3, putting the graphite crucible in the S2 into a vacuum sintering furnace, closing the furnace, and vacuumizing to be less than or equal to 10 DEG^-5After Pa, filling rare gas to the required pressure; the filling flow of the rare gas is 50mL/min, the filling time is 50min, the rare gas is Ar gas, and the required pressure is set to be 800 Toor.

And S4, heating to the required temperature according to a certain heating rate for high-temperature synthesis, cooling after 15 hours, and stopping the furnace to take out the sample.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.