基于蓝宝石衬底生长GaN的立式HVPE控制系统设计

Design of Vertical HVPE Control System for Growing GaN Based on Sapphire Substrate

为了实现氢化物气相外延(HVPE)技术在蓝宝石衬底上外延生长氮化镓(GaN)过程的全自动控制,进一步提高系统的精确性和稳定性,设计了一种新型HVPE控制系统。该控制系统选用可编程逻辑控制器(PLC)为控制器,采用组态王开发系统监控软件。利用模糊推理机制和仿真分析,设计模糊比例积分微分(PID)控制器,提高反应室温区控制的快速性与稳定性。构建大、小质量流量通路,精准控制HVPE系统压力与质量流量,并进行控制系统性能测试。结果表明,该控制系统能较好地实现对GaN生长过程的自动监控,成功在蓝宝石衬底上生长出高质量6英寸(1英寸=2.54 cm)GaN,与现有的HVPE制备技术及监控手段相比,其自动控制程度更高,系统实时响应更快,更具实际生产应用价值。

A new control system for hydride vapor phase epitaxy(HVPE) was designed to realize the automatic control of the epitaxial growth process of gallium nitride(GaN) prepared by the HVPE technique on the sapphire substrate and further improve the precision and stability of the system.In the control system,the programmable logic controller(PLC) was selected as the controller,Kingview was used to develop the system monitoring software.Fuzzy proportional-integral-derivative(PID) controller was designed by using fuzzy reasoning mechanism and simulation analysis to improve the celerity and stability of temperature control in the reaction room temperature area.Large and small mass flow paths were constructed to accurate control the pressure and mass flow of the HVPE system,and the performance test of the control system was performed.The results indicate that the control system can automatically monitor the growth process of GaN well,and high quality 6-inch(1 inch=2.54 cm) GaN was successfully prepared on sapphire substrate.Compared with the existing preparation technique and monitoring means for HVPE,the degree of automatic control of the system is higher and the real-time response is faster,and it has more practical production and application value.