Production of Reduced Defect Density (112) Silicon Wafers Utilizing Ultra- Gentle, Chemical Mechanical Smoothening (CMS) Process

Next generation infra-red focal plane array applications for night vision systems require high quality, large area HgCdTe epi-layers. Such layers are only possible with the use of (112) Si substrates that are of high quality with surfaces that are pristine and devoid of defects. However, commercially available (112) Si surfaces typically have the presence of a large number of COP (crystal originated particle) defects, scratches, and surface defects that lead to the broadening of X-ray rocking curve. This leads to poor crystalline quality. Such defects arise due to CMP (chemical mechanical polishing) processes used by the industry in polishing these wafers. Sinmat has developed a new polishing process that can eliminate COP defects, scratches, and surface contamination. The chemical mechanical smoothening (CMS) processes developed as a part of the Phase I effort, enhance the crystalline quality of (112) Si wafers. As a part of the Phase II effort, Sinmat will further develop and optimize the ultra-smooth and ultra-gentle CMS polishing process. The company will also conduct joint-testing, development and integration studies with end users of (112) Si wafers.