The liquid-phase deposition (LPD) of SiO2 at 50 degreesC on Ge substrates is investigated. Silicic acid (SiO2.xH(2)O) is used to saturate hydrofluorosilicic acid at 30 degreesC and this shortens the time required for solution preparation to 3 h. The growth rate of LPD oxide on Ge is much slower than that of LPD oxide on Si at the beginning of the deposition process, while surface roughness of LPD oxide on Ge is larger than that of LPD oxide on Si. A metal-oxide-semiconductor tunneling diode on Ge is fabricated using the LPD oxide. The tunneling current of the Ge diodes at inversion bias increases as LPD oxide thickness increases, indicating that the trap density in the LPD oxide increases with increasing oxide thickness, and the current transport is dominated by the trap assistant tunneling. (C) 2002 The Electrochemical Society.