Surface Characterization of p-Type Si Etched in Chlorine-Containing Plasma Under Photo-Assisted Etching Conditions

Plasma etching is technique that is routinely used in today’s chip manufacturing process. This is still a technology that needs a better understanding and control as integrated circuit dimensions continue to shrink. Surface characterization was performed on p-Si samples etched for different time periods under photo-assisted etching (PAE) conditions in Cl₂ – containing plasmas. AFM and SEM were used to characterize etched wafers. It was shown that surface contamination can result in undesired surface features (hillocks). In addition, crystallographic etching was observed, resulting in formation of surface pyramid structures due to faster etching of the (100) over the (110) plane.