Sacrificial Oxide With Uniform Thickness

摘要

A semiconductor device includes a silicon-based substrate, a gate structure and a laminated sacrificial oxide layer. The gate structure is on the silicon-based substrate. The laminated sacrificial oxide layer has a first portion on the silicon-based substrate and a second portion conformal to the gate structure, in which a first thickness of the first portion is substantially the same as a second thickness of the second portion. The laminated sacrificial oxide layer includes a native oxide layer and a silicon oxy-nitride layer. The native oxide layer is on the silicon-based substrate and conformal to the gate structure. The silicon oxy-nitride layer is conformal to the native oxide layer.