Sonochemical Passivation of Si and SiGe Heterostructures
Аndriy Nadtochiy, Artem Podolian, Oleg Korotchenkov
Faculty of Physics, Taras Shevchenko National University of Kyiv, Kyiv 01601, Ukraine
To improve the carrier lifetime performance of Si and SiGe heterostructures, sonochemical treatments in hydrocarbon solutions of chloroform (CHCl3) and dichloromethane (CH2Cl2) is proposed. It is believed that the solutions are decomposed into hydrocarbon chains due to extreme temperatures, pressures and cooling rates in the vicinity of collapsing cavitation bubbles and at the etchant/solid interfaces. Surface photovoltage (SPV) transient measurements, scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDX) were performed to characterize the near-surface sonochemical transformations. Increased SPV signals with prolonged decay times are observed, which can be understood as due to the passivation of Si and SiGe layers in hydrocarbon solutions. It is believed that the reported technique can be used for the surface passivation in fabricating Si and SiGe-based microelectronic devices.