压电陶瓷阀在真空磁控反应溅射中的特性

Flow-Rate Control Characteristics of Piezo-Valve in Reactive Magnetron Sputtering

在制备不锈钢-氮化铝(SS-AlN)金属陶瓷集热管的真空磁控溅射镀膜线上,采用PCV25型压电陶瓷阀作为反应气体氮气N2流量输出的驱动元件,实现反应溅射AlN反馈控制。研究了不同环境温度下压电阀偏置电压Vo对N2输出流量Q的影响。实验研究表明,在Vo先增加再减少的过程中,Q相应变化呈现迟滞特性。同时,该迟滞特性受压电阀工作的环境温度影响,环境温度越低迟滞特性越明显。例如与40℃相比,当环境温度为25℃时,压电阀的阈值电压小,饱和电压大,有效工作范围宽,且在压电阀有效工作范围内,N2输出流量Q随偏置电压Vo变化速率小。结合压电陶瓷阀的特性,优化设置反应溅射反馈控制参数,在高于30kW的溅射功率下,实现反应溅射AlN工艺稳定,制备厚度约为70 nm的AlN薄膜在可见光和太阳光范围内吸收几乎为零。

The characteristics of gas flow rate control with the piezoelectric ceramics valve were experimentally eval- uated in deposition of the stainless steel-aluminum nitride（SS-A1N）coatings by reactive magnetron sputtering on industrial scale. The impacts of temperature and bias voltage on N2 flow rate were studied. The results show that the bias voltage and temperature affect the hysteresis of the N2 flow rate in different ways. For example, as the bias varied in an increase-de- crease mode, a lower temperature resulted in a stronger hysteresis. The variations of the bias, in the operation range, were found to weakly affect the N2 flow rate, and the bias changed in proportion to the control voltage, with a slop independent of the temperature. The 70 nm thick SS-AIN coating, continuously grown under optimized conditions, has zero absorption of both visible light and solar irradiation.