Detection of thermal donors from electrically active oxygen interstitials by optical second harmonic generation

Substrate resistivity stability has become the most critical control for radio frequency (RF) device manufacturing. In this paper, we demonstrate nonlinear optics based metrology to measure electrically active oxygen interstitial sites (Oi) in high resistive bulk Si wafers, which are vulnerable to electric and mechanical property drift during device fabrication. Time dependent second harmonic generation (TD-SHG) governed by electric-field induced second harmonic (EFISH) effect provides consistent detection of thermal donors originating from Oi distributed near Si interface. The successful concept proof can be extended to test pad design for in-line monitor of substrate resistivity variations from annealing processes.