Design And Research Of MPCVD Reaction Chamber Based On Horizontal Flow

Current domestic and international researches on the design of MPCVD usually focus on the microwave source coupling,while ignore the design that MPCVD should be considered as CVD device,which leads to obvious shortcomings.Therefore,,a concept of horizontal flow MPCVD is proposed and preliminary designing is conducted based on the simulated investigation of film growth and energy coupling in this thesis.This research designs a horizontal flow chamber structure.Based on the finite anylysis of the structure,it sets up a mathmatical model coupling fluid,heat transfer,mass transfer,chemical reaction and surface growth kinetics.Firstly,the effect of different substrate rotating on the growth of films was studied.The results show that the rotating speed of 0 r/min could result in a certain gradient of the film growth rate in the flow direction.When the rotating speed is low,the fluctuation of distribution of film growth rate on the substrate surface is small.The high rotating speed could improve the uniformity of distribution of the film growth rate along the circumferential direction,but results in a gradient of the film growth rate in the radical direction.Accordingly,the substrate rotation is classified into three modes,static mode,low speed mode and high speed mode.The influences of different structure and processing parameters on the growth uniformity of film in these three modes were studied respectively.The results show that,in static mode,the growth uniformity of the films can be improved by three ways,namely adding compressed air port,setting up different chamber top structure and increasing the substrate temperature.In high speed mode,the optimum uniformity of film deposition could be obtained under the condition of H=70mm,oblique groove structure,v=1.2m/s,p=2000pa and T=1000K.In low speed mode,a uniform state of the film growth can be maintained under various structural and technological parameters.Based on microwave energy coupling,a new type of metal ring tunable horizontal flow MPCVD resonant cavity was designed.By FEM optimization,the basic dimensionparameters of the cavity were set as R1=75mm,H1=50mm,R2=190mm,H2=75mm,R3=111.4mm,H3=75mm,and the radius and height of convex platform were set as R4=28mm,H4=4mm.At last,the tuning performance and plasma density of the designed cavity were verified.The practicability of our design was illustrated by comparing with the reports in relative literature.