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对最近所发表的文献的评述指出,激光退火是一项可以广泛地应用于制造半导体器件中通常所需要的热过程的技术。评论了用Q-开关红宝石(λ=0.69μm)和Nd:YAG(λ=1.06μm)激光以及连续波(CW)激光的实验结果。所讨论的各种应用包括注入损伤的退火、纯半导体表面区的电激活缺陷的退火以及在硅表面形成金属-硅化物的激光感生表面反应。建立了激光退火的一维热模型,并用来模仿在很宽的脉冲持续时间和吸收系数的范围内硅片内的热的演变,吸收系数由所选择的激光波长决定。这种模型专门用来预测阈值脉冲能量、再结晶速度、熔融深度以及表面沸腾的开始。将模型与实验数据作了比较,发现在很宽的脉冲时间(2×10~(-8)-2×10~(-4)sec)和吸收系数(10~2-10~6cm~(-1))范围内一致性很好。特別是计算了单晶片上的无定形表面层所增加的光耦合效应,并发现了与离子注入损伤的激光退火的实验非常一致。
A review of recently published literature states that laser annealing is a technique that can be widely applied to the thermal processes commonly required in the manufacture of semiconductor devices. The experimental results with Q-switched ruby (λ = 0.69 μm) and Nd: YAG (λ = 1.06 μm) and continuous wave (CW) lasers are reviewed. Various applications discussed include annealing for implant damage, annealing for electrically active defects in purely semiconductor surface regions, and laser-induced surface reactions that form metal-silicides on the silicon surface. A one-dimensional thermal model of laser annealing was established and used to simulate the evolution of heat within the silicon wafer over a wide range of pulse durations and absorption coefficients, the absorption coefficient being determined by the laser wavelength selected. This model is designed to predict the threshold pulse energy, recrystallization rate, melt depth, and the onset of surface boiling. Comparing the model with the experimental data, it is found that under the condition of very wide pulse time (2 × 10 -8 -2 × 10 -4 sec) and absorption coefficient (10 2-10 ~ 6 cm -1) 1)) within the scope of consistency is very good. In particular, the increased optical coupling effect of the amorphous surface layer on a single wafer was calculated and it was found that the experiment was very consistent with the laser annealing of ion implantation damage.