垂直式MOCVD反应器中热泳力对浓度分布的影响分析

Influence of Thermophoretic Force on Precursor Concentration and Thin Film Growth in a Vertical MOCVD Reactor

从分子动力学理论出发,推导出垂直式MOCVD反应器中热泳力和热泳速度与温度、温度梯度、压强、粒子直径的关系式,以及热泳速度与扩散速度、动量速度平衡时的关系式。在典型的生长条件下,计算得到在温度T=605K时,热泳速度与扩散速度、动量速度动量平衡,TMGa浓度达到最大。然后在不考虑化学反应和考虑化学反应两种情况下,针对垂直式MOCVD反应器内的热泳力对粒子浓度分布和沉积的影响进行数值模拟,模拟给出反应粒子在反应器不同进口温度、衬底温度时的温度分布、浓度分布和反应速率。并与文献中的实验值进行对比,模拟结果与实验值有很好的吻合。

In vertaical reactor, the expressions of thermophoretic force and thermophoretic velocity for GaN MOCVD growth were derived. Then the balance equation between thermophoretic velocity and diffusion velocity, momentum velocity for TMGa molecules in a vertical MOCVD reactor was also derived. It was determined that most TMGa molecules reside at the position between the temperature of 500 K and 800 K. Numerical simulations are performed considering the case of gas transport only and the case with chemical reactions. The influences of thermophoretic force on deposition rate and concentration distribution are obtained for varying inlet and substrate temperatures. Good correspondence is obtained by comparison of simulation results with experimental literature values.