The properties of SiO2 films using direct photo-chemical vapor deposition on strained SiGe layers

Low temperature silicon-dioxide (SiO2) layers were deposited on strained SiGe by using direct photo-chemical vapor deposition (DPCVD) with a deuterium lamp as the excitation source. It was found that the deposition rate increases linearly with the chamber pressure. The Auger electron spectroscopy profile shows that neither was Ge rejected nor was a Ge-rich layer formed after devices were fabricated. The capacitance-voltage (C-V) measurements show that the flat-band voltage is about −1.1 V with an effective oxide charge of about 7 × 1010 cm−2 and interface trap density of 3 × 1011 cm−2 eV−1. At room temperature, the leakage current is about 3 × 10−9 A/cm2 under a 2 × 106 V/cm electric field. The breakdown field can reach over 16 MV/cm at 1 μA/cm2 for these SiGe metal-oxide semiconductor (MOS) diodes.