Suppressing Hexagonal Defects in Ex Situ Remote Plasma Dry Etch Processing

Hexagonal silicon oxide defects induced by an ex-situ remote plasma dry etch pre-clean process (SiCoNi^TM) were observed at the NPN emitter step of a 40 nm BiCMOS device, leading to high defect density and device yield loss. In this work, a systematic investigation was performed to identify the root cause and formation mechanism of these defects. Comprehensive characterization and experiments reve