Non-silicon metal-insulator-semiconductor (MIS) devices and methods of forming the same. The non-silicon MIS device includes a gate dielectric stack which comprises at least two layers of non-native oxide or nitride material. The first material layer of the gate dielectric forms an interface with the non-silicon semiconductor surface and has a lower dielectric constant than a second material layer of the gate dielectric. In an embodiment, a dual layer including a first metal silicate layer and a second oxide layer provides both a good quality oxide-semiconductor interface and a high effective gate dielectric constant.