Process temperature dependent high frequency capacitance-voltage response of ZrO2/GeO2/germanium capacitors

Abstract

ZrO 2 / GeO 2 dielectrics are grown on germanium substrates by Atomic Layer Deposition (ALD) at substrate temperatures of 150, 200, and 250 °C, respectively. The impact of the deposition temperature on the electrical and structural properties of MOS capacitors is investigated. A significant influence of the ALD temperature on the high frequency capacitance in inversion can be observed, resulting in a shift of the minority carrier response time from 1.15 to 0.2 μs. Time-of-flight secondary ion mass spectroscopy investigations indicate a distinctive depletion of interfacial GeO at higher ALD temperatures, which give rise to trap levels near the oxide/Ge interface.