Epitaxial Al2O3 films on Si by low-pressure chemical vapor deposition

Heteroepitaxial Al2O3 films were grown successfully on (100)Si substrates at substrate temperatures above 1000 °C by low-pressure chemical vapor deposition with the use of N2 bubbled Al(CH3)3 and N2O. From reflection high-energy electron diffraction analysis, the epitaxial films were found to be γ-Al2O3 with an orientation relation of (100)Al2O3//(100)Si. Capacitors with 700-Å-thick Al2O3 films as gate insulators were fabricated and showed high-frequency capacitance-voltage characteristics without hysteresis. An interface state density of 1.7×1011 cm−2 eV−1 was observed by using quasistatic capacitance-voltage measurements. The leakage current was 9.7×10−11 A/cm2 at a gate voltage of 3.0 V.