Silicon used in semiconductor electronic devices is one of the most widely used material in information technology and power electronics industry. The silicon is found to be the suitable material allowing reduced power loss in power devices. If power loss can be even reduced further, the demand for silicon power devices will increase significantly for industrial and domestic purpose. In order to reduce power loss more, the productivity of silicon epitaxial growth should be improved.
Researchers at Yokohama National University in Japan led by Professor Hitoshi Habuka successfully increased the silicon epitaxial growth rate above saturation of the silicon epitaxial film, based on a new idea of parallel Langmuir process. To increase the growth rate above saturation, silicon hydride (SiHx) was added with SiHCl3-H2. Studies were evaluated by using rate theory for the parallel Langmuir process. Their research work is now published in journal, Materials Science in Semiconductor Processing.
The research team synthesized the silicon epitaxial film SiHCl3-SiHx-H2 in a reactor. The silicon wafer was heated by halogen lamps. The monomethylsilane gas was introduced with the SiHCl3 and H2 gases from the inlet at atmospheric pressure. For safety reasons, this experiment used SiH3CH3 gas instead of SiH4 gas. The silicon epitaxial growth rate was numerically calculated by considering the heat and gas flow in the entire reactor and the surface chemical reactions using the software Fluent (ANSYS).
The authors showed that epitaxial growth rate by SiHx was significantly lower than that by SiHCl3. They also found that increasing the SiHx flow rate, the silicon epitaxial growth rate can be increased further. Moreover, SiHx enhanced the SiHCl3 consumption.
The study demonstrated the existence of parallel Langmuir process by the evaluation of rate equation and rate constant for silicon epitaxial growth in a SiHCl3-SiHx-H2 system. The general form of rate equation will help applying the concept to various epitaxial growth processes. Thus, parallel Langmuir process is found to be effective in epitaxial growth rate above saturation and will help producing various semiconductor devices, such as those with less power loss.
Toru Watanabe, Ayami Yamada, Ayumi Saito, Ayumi Sakurai, and Hitoshi Habuka. Parallel Langmuir processes for silicon epitaxial growth in a SiHCl3-SiHx-H2 system. Materials Science in Semiconductor Processing, Volume 72 (2017), Pages 134–138.
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