Types of Thin Films Used in Semiconductor Processing Thermal Oxides Dielectric Layers Epitaxial Layers Polycrystalline Silicon Metal Films
Uses for Deposited Films
Dielectric Films • Used for insulation and passivation • Typically deposited via atmospheric pressure CVD, low pressure CVD, and plasma-enhanced CVD • Typical films include: – Silicon Dioxide – Silicon Nitride – Low dielectric constant materials – High dielectric constant materials
Epitaxy • Related to silicon crystal growth • Single-crystal semiconductor layer is grown on a single-crystal substrate • Homeoepitaxy if grown layer and substrate layer are the same • Heteroepitaxy if the grown layer and substrate layer are different • Done via: – Chemical Vapor Deposition (CVD) – Molecular Beam Epitaxy (MBE)
Lattice Matching Issues in Epitaxy
Critical Layer Thickness for Defect. Free Strained Layer Epitaxy
Why use Polysilicon?
Metal Connections
Deposition Requirements
Deposition Issues
Deposition Issues
Deposition Issues Are Related to Aspect Ratio of Features
Industry Roadmap
Deposition Tools
Atomospheric Pressure Chemical Vapor Deposition (APCVD) Hardware
Improving APCVD Uniformity
Steps in a CVD Process
Silicon Doping with Arsenic and CVD Film Growth process