Growth of Ge Thick Layers on Si(001) Substrates Using Reduced Pressure Chemical Vapor Deposition

Growth of Ge thick layers with and without a low temperature Ge buffer has been investigated using reduced pressure chemical vapor deposition with emphasis on the evolution of surface morphology and its roughness. Growth at 400 °C exhibited a 200 s incubation period for which about 1 equivalent monolayer of Ge was deposited with a surface roughness of around 0.1 nm followed by an abrupt increase due to an island growth. Higher growth temperature resulted in shorter or no observed incubation period and led to rougher surface due to larger size of islands. Ge layers grown at 600 °C on at low temperature Ge buffer first grown at 400 °C exhibited around 1 nm surface roughness independent of the layer thickness, which is much lower than those at 400–600 °C without the low temperature buffer. The Ge thick layer with the low temperature Ge buffer had thinner defective interface of Ge/Si than that without the buffer.