Gentle and Non-Contact Slurries for Atomic Scale Chemical Mechanical Smoothening and Passivation of GaSb Substrates

"Gallium Antimonide based hetrostructures have attracted significant interest in recent years because of their applications ranging from 100 GHz high speed logic circuits. For rapid commercialization of these devices, it is necessary to obtain, highsurface quality, surface passivated GaSb substrates, which do not exhibit surface quality variations from wafer to wafer, and vendor to vendor. This problem has been attributed to poor surface preparation techniques adopted by the vendors. Standardchemical etching/polishing, mechanical or chemical mechanical polishing (CMP) has not led to optimal results, because of their inability to atomically smoothen the surface and form nanoscale passivation layers. In this project Sinmat Inc. proposes to useand further extend its proprietary chemical mechanical smoothening and passivation(CMSP) technique and non contact abrasive-free CMP(AFCMP) process to achieve atomic level smoothening and passivation on GaSB surfaces. The CMSP technique is based onpressure-dependent polishing to achieve atomic level smoothening and passivation whereas, in AFCMP process, the chemicals form a soft layer which can be removed by the polishing pad. No abrasives are present, which leads to a defect free process. SinmatInc. working with the University of Florida also proposes to develop a measurement protocol based on sophisticated X-Ray methods to characterize the surface quality and passivation in GaSB wafers. Sinmat