Reactions: H20+2* *E vacant surface site WFla+ 6* fIM+ w F(a)+He HF 9)+2 If the step 3 is rate limiting the rate law will obey the equation: Growth rate X 0HBFxP(H2 2P(WF 6)6 Tungsten deposition using WF6/ H2 gas mixtures in plasma-assisted CVD and laser-assisted CVd are potential alternatives to the thermal or conventional metal CVD 6:化学吸附率
Reactions: H2(g) + 2* 2H(a) *= vacant surface site (1) WF6(g) + 6* 6F(g) + W(s) (2) F(a) + H(a) HF(g) + 2* (3) If the step (3) is rate limiting, the rate law will obey the equation: Growth rate ∝ θHθF∝P(H2 ) 1/2P(WF6 ) 1/6 Tungsten deposition using WF6/H2 gas mixtures in plasma-assisted CVD and laser-assisted CVD are potential alternatives to the “thermal” or conventional metal CVD. θ：化学吸附率
WF si Tungsten thin film can be deposited selectively on silicon and metal surfaces without nucleation and growth on adjacent insulators(e.g, SIO2 and Si3N4) Reduction(displacement process) 2WF60+3sil→2Wl+3SF increasing temperatur to 450.C WF6+3Si→Ws)+3sig
WF6 + Si Tungsten thin film can be deposited selectively on silicon and metal surfaces, without nucleation and growth on adjacent insulators (e.g., SiO2 and Si3N4 ). Reduction (displacement process): 2WF6(g) + 3Si(s) 2W(s) + 3SiF(g) increasing temperatur to 450℃ WF6(g) + 3Si(s) W(s) + 3SiF(g)
通过这个反应,在硅的位置上提供选择性的 沉积,形成触点。硅被消耗掉,而钨沉寂 下来取代了硅。当形成了一个薄层的钨后, 反应被自动终止,因为WF6气体的扩散受 到阻碍。所以它的还原是自我限制的。当 存在氢气时,这个表面可以通过离解吸附 继续沉积钨。而在SO2的表面是不会继续 发生的
通过这个反应，在硅的位置上提供选择性的 沉积，形成触点。硅被消耗掉，而钨沉寂 下来取代了硅。当形成了一个薄层的钨后， 反应被自动终止，因为WF6气体的扩散受 到阻碍。所以它的还原是自我限制的。当 存在氢气时，这个表面可以通过离解吸附 继续沉积钨。而在SiO2 的表面是不会继续 发生的
保持选择性非常难。因为在SiO2上的成核会 普遍发生,在S和SO2的界面上和SO2表 面的缺陷和杂质上都会产生钨的形核。因 此,在工艺过程中,表面原位洁净化步骤 是需要的。另外,还会发生钨的迁移,钨 形成了WF5
保持选择性非常难。因为在SiO2上的成核会 普遍发生，在Si和SiO2的界面上和SiO2表 面的缺陷和杂质上都会产生钨的形核。因 此，在工艺过程中，表面原位洁净化步骤 是需要的。另外，还会发生钨的迁移，钨 形成了WF5
WF6+ SiH4 The addition of siHg into the WF6/H2 gas stream effectively suppresses the reduction reaction of WF6 y the si substrate since the following reactions with SiHa are thermodynamically and kinetically favored The overall reaction can be expressed as WF6lo)+2SiHalo)- Wis)+ 2SiHF3ln +3H2(g) 250C 2WF 6(g)+ 3SiH4(g)-+ 2W+ 3SiF 4(9)+ 6H2(g) >600%C
WF6 + SiH4 The addition of SiH4 into the WF6 /H2 gas stream effectively suppresses the reduction reaction of WF6 by the Si substrate since the following reactions with SiH4 are thermodynamically and kinetically favored. The overall reaction can be expressed as : WF6(g) + 2SiH4(g) W(s) + 2SiHF3(g) + 3H2(g) 250 ℃ 2WF6(g) + 3SiH4(g) 2W + 3SiF4(g) + 6H2(g) ＞600℃