石英钟罩对MPCVD金刚石膜沉积的影响

Effects of Quartz Bell Jar on Diamond Film Deposited by MPCVD

为了提高高品质金刚石膜的沉积速率,利用CST三维电磁场仿真软件,模拟了Diamo Tek700微波等离子体化学气相沉积设备中,在忽略等离子体存在的前提条件下,石英钟罩的厚度和形状对沉积金刚石膜的基片表面电场分布的影响。同时采用壁厚3 mm,3.5 mm和4 mm的平顶和壁厚4 mm的圆顶钟罩分别进行了金刚石膜的沉积实验。模拟结果显示,对于同一类型的石英钟罩,壁厚的变化（3-4 mm）对基片表面平均电场影响不大;而壁厚相同的圆顶钟罩情况下基片表面平均电场则比平顶的高出10%。壁厚4 mm的圆顶石英钟罩得到了相对较高且均匀的电场分布。结果表明,沉积速率与模拟的基片表面电场强度存在对应关系;采用壁厚4 mm圆顶钟罩与原厂设计的壁厚3 mm平顶钟罩相比,在相同的工艺条件下,沉积速率提高一倍,达到1.4μm/h。

In order to improve the deposition rate of the quality of diamond film,the effects of geometric dimension and shape of the bell jar on electric field distribution at the substrate surface under the condition of without plasma have been studied by CST MWS software based on a Diamo Tek700 MPCVD system. The flat-top bell jars with wall thickness of 3 mm,3. 5 mm and 4 mm and the dome shaped bell jar of 4 mm thick wall were used to deposit diamond films. The results indicate that for the flat-top bell jar,the effect of the wall thickness on electric field distribution was not so large. However,mean electric field strength at substrate surface with the dome shaped bell jar was found to be 10% higher than that with the flat-top one. Experimental results show that deposition rate was well consistent with the mean electric field strength at substrate surface. Under the same growth process condition,the deposition rate with the dome shaped bell jar of 4 mm thick wall reached 1. 4 μm /h,which was doubled compared to those with the flat-top bell jar of 3 mm thick wall.