[材料科学]半导体材料生长55-66.ppt

Dry Etching Dry etching methods Glow discharge methods Dry physical etching (Sputter etching) Plasma assisted etching Dry chemical etching (Plasma etching) Reactive ion etching (RIE) Ion beam methods Ion milling Reactive ion beam etching Chemical assisted ion milling Common materials to dry etch Si, SiO2, Si3N4, Al, W, Ti, TiN, TiSi2, Photoresist Difficult materials to dry etch Fe, Ni, Co, Cu, Al2O3, LiNbO3, etc. RF-powered plasma etch system Barrel plasma system Etchants and etch products Plasma assisted etching Plasma assisted etching sequence Take a molecular gas CF4 Establish a glow discharge CF4+e ? CF3 + F + e Radicals react with solid films to form volatile product Si + 4F ? SiF4 ? Pump away volatile product (SiF4 ?) Chemical vs. chemical/physical etching Effect of the inhibitor Plasma assisted etching Dry chemical etching (Plasma etching) RF energy is applied to a separate electrode with the substrates grounded. Material is removed from the substrate by chemical means. Purely chemical etching Glow discharge is used to produce chemically reactive species (atoms, radicals, or ions) Reactive-ion Etching (RIE) If RF energy is applied to the substrates in a low pressure halogen-rich environment, material can be removed by both chemical means and ion bombardment of the substrate surface. Greater control over line widths and edge profiles is possible with oxides, nitrides, polysilicon and aluminum. A combination of physical/chemical etching Accomplished by replacing the neutral gas in a r.f. sputtering system by one or more chemical species Glow discharge is used to produce chemically reactive species (atoms, radicals, or ions) and chemically inert ions Highly anisotropic etching 其他简单工艺设备 高温退火炉 快速退火炉 闭管蒸发方法 电化学镀膜 介质阻挡 工艺实例（一） 陷光结构类型 制作金字塔绒面 制作多孔硅 玻璃基片织构 压花法 溶胶凝胶法 其他材料介质膜 工艺实例（三） 第6结课（ II-VI 材料特性） Semiconductor materials classification Elemental semiconductor--Si, Ge Compound semiconductor IV-IV---SiC III-V----AlP,AlAs,GaAs,GaSb,InP,In