Interface property of silicon nitride films grown by inductively coupled plasma chemical vapor deposition and plasma enhanced chemical vapor deposition on In0.82Al0.18As

Abstract

Au/silicon nitride/In0.82Al0.18As metal insulating semiconductor (MIS) capacitors were fabricated and then investigated by capacitance voltage (C–V) test at variable frequencies and temperatures. Two different technologies silicon nitride (SiNx) films deposited by inductively coupled plasma chemical vapor deposition (“ICPCVD”) and plasma enhanced chemical vapor deposition (“PECVD”) were applied to the MIS capacitors. Fixed charges (Nf), fast (Dit) and slow (Nsi) interface states were calculated and analyzed for the different films deposition MIS capacitors. The Dit was calculated to be 4.16×1013cm−2eV−1 for “ICPCVD” SiNx MIS capacitors, which was almost the same to that of “PECVD” SiNx MIS capacitors. The Dit value is obviously higher for the extended wavelength InxGa1−xAs (x>0.53) epitaxial material as a result of lattice mismatch with substrate. Compared to the results of “PECVD” SiNx MIS capacitors, the Nsi was significantly lower and the Nf was slightly lower for “ICPCVD” SiNx MIS capacitors. X-ray photoelectron spectroscopy (XPS) analysis shows good quality of the “ICPCVD” grown SiNx. The low temperature deposited SiNx films grown by “ICPCVD” show better effect on decreasing the dark current of InxGa1−xAs photodiodes.