The purpose of cleaning SGOI (silicon germanium on insulator) and SiGe (silicon germanium) substrates is to remove any impurities or contaminants that may be present on the surface. This ensures that the subsequent layers of materials deposited on the substrate will have a clean and uniform surface to adhere to, resulting in better device performance and reliability.
The most common contaminants found on SGOI and SiGe substrates include organic residues such as oils, dust, and particles from handling, as well as inorganic residues such as oxides, metals, and salts from the manufacturing process.
There are several methods for cleaning SGOI and SiGe substrates, including wet chemical etching, plasma cleaning, and UV ozone cleaning. Wet chemical etching involves immersing the substrate in a solution that dissolves and removes contaminants. Plasma cleaning uses a low-pressure gas discharge to remove contaminants through reactive chemical reactions. UV ozone cleaning uses ultraviolet light to break down and remove organic contaminants.
The cleaning process is crucial in the fabrication of SGOI and SiGe devices as it directly impacts the quality and performance of the final product. Even small amounts of contaminants can significantly affect the electrical and mechanical properties of the device, leading to device failure or reduced lifespan.
Yes, there are some special precautions to take when cleaning SGOI and SiGe substrates. It is essential to use cleanroom protocols, such as wearing proper attire and using cleanroom equipment, to prevent contamination during the cleaning process. Additionally, it is crucial to follow the recommended cleaning procedures and avoid using harsh chemicals that can damage the substrate or alter its properties.