Surface composition and characteristics of oxide‐free Ga1–xAlxAs (110) Schottky barriers

Surface composition of a Ga1–xAlxAs (110) face with different aluminum concentrations (0.2?x?0.8) were studied by Auger electron spectroscopy (AES). Native oxide layers of ∠30 A were found on the surfaces. The surface oxide‐layer thickness is very insensitive of aluminum concentration. Crystals of different aluminum content have the same native oxide layers. Oxygen exists at the crystal surfaces in the form of aluminum oxide Al2O3. Ultrahigh vacuum (UHV) technologies and ion sputtering are combined to fabricate oxide‐free Schottky barriers and the I–V characteristics were analyzed. A leakage current in the μA range and breakdown voltage above 107V m−1 were observed.