The effect of substrate holder size on the electric field and discharge plasma on diamond-film formation at high deposition rates during MPCVD

• Published in: Plasma science & technology Vol. 19; no. 9; pp. 107 - 113
• Main Author: 安康 陈良贤 刘金龙 赵云 闫雄伯 化称意 郭建超 魏俊俊 黑立富 李成明 吕反修
• Format: Journal Article
• Language: English
• Published: IOP Publishing 01.09.2017
• Subjects: CVD金刚石膜; deposition rate; diamond film; marginal discharge; MPCVD; 不均匀等离子体; 放电等离子体; 沉积速率; 特征尺寸; 等离子体密度; 金刚石薄膜; 非均匀等离子体
• ISSN: 1009-0630; 1009-0630
• DOI: 10.1088/2058-6272/aa7458

The effect of the substrate holder feature dimensions on plasma density（ne）, power density（Qmw） and gas temperature（T） of a discharge marginal plasma（a plasma caused by marginal discharge） and homogeneous plasma were investigated for the microwave plasma chemical vapor deposition process. Our simulations show that decreasing the dimensions of the substrate holder in a radical direction and increasing its dimension in the direction of the axis helps to produce marginally inhomogeneous plasma. When the marginal discharge appears, the maximum plasma density and power density appear at the edge of the substrate. The gas temperature increases until a marginally inhomogeneous plasma develops. The marginally inhomogeneous plasma can be avoided using a movable substrate holder that can tune the plasma density, power density and gas temperature. It can also ensure that the power density and electron density are as high as possible with uniform distribution of plasma. Moreover, both inhomogeneous and homogeneous diamond films were prepared using a new substrate holder with a diameter of 30 mm. The observation of inhomogeneous diamond films indicates that the marginal discharge can limit the deposition rate in the central part of the diamond film. The successfully produced homogeneous diamond films show that by using a substrate holder it is possible to deposit diamond film at 7.2 μm h~（–1）at 2.5 kW microwave power.