The separation of generation lifetimes of Si and SiGe using capacitance-transient measurements on MOS capacitors formed by plasma anodisation of Si:Si_0.9Ge_0.1:Si substrates

摘要

A simple technique leading to the measurement of minority carrier lifetimes of UHV compatible LPCVD Si and SiGe by C-t depth profiling of Metal:Oxide:SiSiGe:Si structures is reported. A high quality gate oxide is realised by low temperature (<100degC) plasma anodisation thereby reducing any oxidation effects on the underlying epitaxial layer quality. Capacitance response times were observed for an impurity concentration of ～2.5 x 10~17 cm~-3, giving rise to generation lifetimes of the Si and Si_0.9Ge_0.1 of >0.55 and 2.6μs respectively, reflective of very high quality epitaxial semiconductor material.