Silicon interfacial passivation layer chemistry for high-k /InP interfaces

The interfacial chemistry of thin (1 nm) silicon (Si) interfacial passivation layers (IPLs) deposited on acid-etched and native oxide InP(100) samples prior to atomic layer deposition (ALD) is investigated. The phosphorus oxides are scavenged completely from the acid-etched samples but not completely from the native oxide samples. Aluminum silicate and hafnium silicate are possibly generated upon ALD and following annealing. The thermal stability of a high-k/Si/InP (acid-etched) stack are also studied by in situ annealing to 400 and 500 °C under ultrahigh vacuum, and the aluminum oxide/Si/InP stack is the most thermally stable. An indium out-diffusion to the sample surface is observed through the Si IPL and the high-k dielectric, which may form volatile species and evaporate from the sample surface.