3.155J6.152J Sputtering process P≈10-100 m Torr cathode Cathode is" target” V≈1kV cathode e Momentum transfer of Ar+ on cathode erodes cathode atoms source atoms Target material(cathode s flux to anode substrate must be conductive or use RF sputtering (later) 6.1523.155 Nov.5.2003 Inside a plasma Cathode e Art impact on cathode electrons ② 1.5eV Faraday dark space ①Ek ②1.5≤Eks3eV③ e. induced no action optical excitation ofAr→ visible glow 6.152J.155J Nov.5.20033.155J/6.152J 6.152J/3.155J Nov. 5, 2003 7 P § 10-100 m Torr cathode anode  V § 1 kV - Ex ve- vAr+ Cathode is “target”, source material cathode anode  V § 1 kV - Mostly-neutral source atoms Target material (cathode) must be conductive …or use RF sputtering (later) Momentum transfer of Ar+ on cathode erodes cathode atoms fi flux to anode, substrate. Sputtering process Ar+ 6.152J/3.155J Nov. 5, 2003 8 ve - vAr+ Ex Cathode Anode x Ar+ impact on cathode fimostly electrons ¿ ¡ ¬ x 1.5eV EK ~ ve - 2 3 eV Ionization glow v f 2 = 2ax ¿ EK e - <~ 1.5eV Cathode dark space, no action ¡ 1.5 < EK e - ~ ~< 3eV e- - induced optical excitation of Ar fi visible glow cathode anode -  Inside a plasma ¬ EK > 3eV fi ionization, High conductivity plasma Faraday dark space