Process engineering of the surface passivation using $(NH_4)_2S$ for the InP MOS capacitor with ALD $Al_2O_3$

Abstract

Ammonium sulfide ($(NH_4)_2S$) is used for the pretreatment of an InP (100) substrate and its conditions are optimized. The capacitance-voltage (C-V) characteristics of InP MOS capacitors are analyzed by changing the concentration and treatment time of the ammonium sulfide solution. It was found that a 10% $(NH_4)_2S$ treatment for 10 min exhibits the best electrical properties in terms of hysteresis and frequency dispersions in the a depletion or accumulation mode. After the InP substrate was passivated by the optimized ammonium sulfide, the results of x-ray photoelectron spectroscopy (XPS) and the extracted interface trap density ($D_{it}$) prove that the growth of native oxide is suppressed