Evidence of electron and hole inversion in GaAs metal-oxide-semiconductor capacitors with HfO ₂ gate dielectrics and α-Si/SiO ₂ interlayers

Evidence of inversion in GaAs metal-oxide-semiconductor capacitors with HfO 2 gate dielectrics and α-Si/SiO 2 interlayers is reported. Capacitors formed on n-GaAs with atomic layer-deposited HfO 2 displayed C-V characteristics with minimum D it of 7 × 10 11 cm -2/eV, while capacitors with molecular beam epitaxy-deposited HfO 2 on p-GaAs had D it=3 × 10 12 cm -2/eV. Lateral charge transport was confirmed using illuminated C-V measurements on capacitors fabricated with thick Al electrodes. Under these conditions, capacitors on n-GaAs (p-GaAs) showed "low-frequency" C-V behavior, indicated by a sharp capacitance increase and saturation at negative (positive) gate bias, confirming the presence of mobile charge at the semiconductor/dielectric interface. © 2006 American Institute of Physics.