多片式热壁MOCVD反应器的设计与数值模拟分析

Design and Numerical Simulation of a Multi-wafer Hot-wall MOCVD Reactor

本文提出一种多反应腔并联的水平热壁MOCVD反应器,反应器上下(左右)壁面都采用高温,减少了热泳力的排斥作用,提高了衬底上方的TMG浓度。由于取消了传统反应器的冷壁,减少了寄生产物的凝结,提高了反应前体的利用率和GaN的生长速率。可以多个反应腔并联生长,从而实现反应器的扩容。针对这种热壁式反应器,结合GaN的MOCVD生长进行了二维数值模拟,计算了不同流速、高度、长度和压力时反应器内流场、温场、浓度场分布以及生长速率,发现存在一个最佳的气体流速、反应器高度和长度条件,在此条件下,反应前体的产生与沉积达到平衡,从而有效抵消反应前体的沿程损耗,实现均匀的GaN生长。

A multi-wafer parallel hot-wall MOCVD reactor was designed,the parallel top and bottom walls of the reactor both placed with wafers and heated.Because there is no temperature gradient between the walls,both thermal convection and thermophoresis can be depressed,the TMG concentration above the substrate can be increased,and the condensation of nanoparticles on the cold wall can be the avoided.Thus the growth rate and precursor efficiency are increased.For the new reactor design,numerical simulation for GaN MOCVD process was conducted.The flow,temperature,concentration fields and GaN growth rate along the susceptor were all predicted under different flow rate,height,length and pressure.The results show that there exists an optimum growth condition for velocity,reactor height and reactor length parameters within certain reactor length,where the generation and consumption of precursors are in balance and uniform growth rate of GaN can be achieved.