China silicon single crystal growth Manufacturers, Suppliers, Factory

We know that further epitaxial layers need to be built on top of some wafer substrates for device fabrication, typically LED light-emitting devices, which require GaAs epitaxial layers on top of silicon substrates; SiC epitaxial layers are grown on top of conductive SiC substrates for building devices such as SBDs, MOSFETs, etc. for high voltage, high current and other power applications; GaN epitaxial layers are built on top of semi-insulating SiC substrates for building HEMTs and other RF applications.

One of the unique properties of semiconductor materials is that their conductivity, as well as their conductivity type (N-type or P-type), can be created and controlled through a process called doping. This involves introducing specialized impurities, known as dopants, into the material to form junctions on the surface of the wafer. The industry employs two main doping techniques: thermal diffusion and ion implantation.

Epitaxial growth refers to the process of growing a crystallographically well-ordered monocrystalline layer on a substrate. Generally speaking, epitaxial growth involves the cultivation of a crystal layer on a single-crystal substrate, with the grown layer sharing the same crystallographic orientation as the original substrate. Epitaxy is extensively utilized in semiconductor manufacturing, such as the production of epitaxial silicon wafers in the integrated circuit industry.

GaN materials gained prominence following the awarding of the 2014 Nobel Prize in Physics for blue LEDs. Initially entering the public eye through fast-charging applications in consumer electronics, GaN-based power amplifiers and RF devices have also quietly emerged as critical components in 5G base stations. In recent years, GaN-based automotive-grade power devices have shown promise, potentially opening new growth avenues for GaN material applications.

SiC's own characteristics determine its single crystal growth is more difficult. Due to the absence of Si:C=1:1 liquid phase at atmospheric pressure, the more mature growth process adopted by the mainstream of the semiconductor industry can not be used to grow the more mature growth method-straight pulling method, the descending crucible method and other methods for growth. After theoretical calculations, only when the pressure is greater than 105 atm and the temperature is higher than 3200 ℃, can we get the stoichiometric ratio of Si:C = 1:1 solution. pvt method is currently one of the more mainstream methods.

Within the silicon carbide (SiC) industry chain, substrate suppliers hold significant leverage, primarily due to value distribution. SiC substrates account for 47% of the total value, followed by epitaxial layers at 23%, while device design and manufacturing constitute the remaining 30%. This inverted value chain stems from the high technological barriers inherent to substrate and epitaxial layer production. Three major challenges plague SiC substrate growth: stringent growth conditions, slow growth rates, and demanding crystallographic requirements. These complexities contribute to increased processing difficulty, ultimately resulting in low product yields and high costs. Furthermore, the epitaxial layer’s thickness and doping concentration are critical parameters directly impacting the final device performance.