A chemical vapor deposition equipment for producing silicon carbide epitaxial wafers

Abstract

The invention provides a method for improving the uniformity of silicon carbide epitaxial wafers, which can be used to grow silicon carbide epitaxial wafers with uniform thickness. By installing a gas flow blocking ring under the gas flow in the reaction chamber, and then placing the silicon carbide substrate on the support table, heating the reaction chamber to the temperature required for epitaxy, passing the reaction gas and carrier gas, and finally on the silicon carbide substrate A silicon carbide epitaxial layer is formed on the bottom. The thickness of the silicon carbide epitaxial wafer obtained by the invention is more uniform, and the device is simple, which is the most feasible and cheapest method for improving traditional equipment, does not require excessive cost input, and is beneficial to industrial production.

Description

【Technical field】 [0001] The invention belongs to the field of chemical vapor deposition, and in particular relates to a chemical vapor deposition equipment for producing silicon carbide epitaxial wafers. 【Background technique】 [0002] Silicon carbide (SiC) is the third-generation wide-bandgap semiconductor material. It has the characteristics of wide bandgap, high critical breakdown electric field, high thermal conductivity, and high carrier saturation drift velocity. It is especially suitable for high-temperature, high-voltage, and high-power power electronics. Semiconductor devices such as semiconductors are of great significance to the development of industries such as hybrid electric vehicles, electric vehicles, solar inverters, and smart grids. [0003] The production of silicon carbide materials, whether it is crystal growth or epitaxial growth, is not easy, and growing high-quality epitaxial wafers is a challenge to the process. The reaction chamber, the cleanlines...

AI Technical Summary

Problems solved by technology

like figure 1 In the traditional horizontal vapor deposition equipment shown, during the epitaxial growth, because the reaction gas source passes through the reaction chamber during the reaction process, there is a "depletion" phenomenon, that is, when the reaction gas flows parallel to the substrate, the inflow of the gas flow The concentration in the direction is higher, because the "consumption" phenomenon has a smaller concentration in the outflow direction of the airflow, so the epitaxial layer on the substrate surface close to the inflow direction of the airflow will be thicker and the epitaxial layer in the outflow direction of the airflow will be thinner

This non-uniformity has a great impact on device fabrication, especially for thicker epitaxial layers

[0004] The patent number is ZL98812328.2, and the patent titled "Growing very uniform silicon carbide epitaxial layer" discloses an improved chemical vapor deposition method. The reactor is heated until the silicon carbide raw material gas forms an epitaxial layer on the substrate in the reactor. The temperature of the raw material gas and the carrier gas flow through the heated reactor to form a silicon carbide epitaxial layer on the substrate. At the same time, the carrier gas includes a mixture of hydrogen and a second gas, wherein the thermal conductivity of the second gas is lower than that of hydrogen. lead, so that the consumption of the raw material gas when passing through the reactor is lower than that of using a single hydrogen as the carrier gas, but the operation process is complicated, and an additional gas source is added, which increases the manufacturing cost

In recent years, silicon carbide epitaxy technology has been very mature in low-voltage devices, but there are still many shortcomings in silicon carbide thick epitaxy technology in high-voltage devices, such as the difficulty of achieving thicker silicon carbide epitaxial layers due to uniformity and surface defects; The growth rate is too low, making the thick SiC epiwafers required to grow high-voltage devices prohibitively expensive

Images