Solid-state zinc-expanding method of GaAs-based epitaxial wafer

Abstract

The invention discloses a solid-state zinc-expanding method of a GaAs-based epitaxial wafer. A ZnO thin film is arranged on the GaAs epitaxial wafer to serve as a zinc source for performing zinc diffusion. The ZnO thin film is arranged on the GaAs epitaxial wafer in a sputtering mode. The temperature of zinc diffusion is 450-550 DEG C, the atmosphere of zinc diffusion is inert gas, preferably, theinert gas is nitrogen. The zinc diffusion source is the ZnO thin film, and is a solid-state source, so that the repeatability and the consistency of the diffusion process are relatively high. When the ZnO thin film is prepared by adopting the sputtering method, a damage layer can be formed on the surface of the epitaxial layer; and zinc atoms can easily enter the epitaxial layer along the damagedefects when zinc diffusion is carried out. An MOCVD reaction chamber is used for zinc diffusion, and the heat transfer mode adopts heat conduction, so that the temperature change of the epitaxial wafer is very fast, and the temperature uniformity of the whole epitaxial wafer is very high, thereby achieving very high diffusion uniformity and consistency.

Description

technical field [0001] The invention relates to a solid-state zinc expansion method for GaAs-based epitaxial wafers, belonging to the technical field of semiconductor technology. Background technique [0002] Thermal diffusion technology is an important step in the manufacturing process of semiconductor devices. Diffusing atoms undergo intense thermal motion at high temperatures, and the substances to be diffused on the surface move to the interior of the semiconductor through atomic gaps or displacements to achieve some special properties. Diffusion technology is relatively mature in silicon devices, and is widely used in semiconductor devices such as Schottky diodes, photodiodes, and photoresistors. In GaAs devices, Zn atoms become the most widely used diffusion source because of their small atomic radius, large diffusion coefficient, and low diffusion temperature. There are two main applications, one is to form a heavily doped P-type region by diffusion, which is used to...

AI Technical Summary

Problems solved by technology

Both of the above two methods use MOCVD to grow ZnO as a solid-state diffusion source, but MOCVD is difficult to grow ZnO at a low temperature, generally above 400°C. At this time, Zn atoms already have a large thermal kinetic energy. Diffusion has already occurred, and the repeatability between batches cannot be fully guaranteed if the temperature is increased for subsequent diffusion.

Images