Interfacial characteristics and band alignments for Zr O2 gate dielectric on Si passivated p-GaAs substrate

The interfacial characteristics and band alignments of high- k Zr O2 on p-GaAs have been investigated by using x-ray photoelectron spectroscopy and electrical measurements. It has been demonstrated that the presence of Si interfacial passivation layer (IPL) improves GaAs metal-oxide-semiconductor device characteristics such as interface state density, accumulation capacitance, and hysteresis. It is also found that Si IPL can reduce interfacial GaAs-oxide formation and increases effective valence-band offset at Zr O2 p-GaAs interface. The effective valence-band offsets of Zr O2 p-GaAs and Zr O2 Sip-GaAs interfaces are determined to be 2.7 and 2.84 eV, while the effective conduction-band offsets are found to be 1.67 and 1.53 eV, respectively.