偏压对电弧离子镀薄膜表面形貌的影响机理

MECHANISM OF EFFECT OF BIAS ON MORPHOLOGIES OF FILMS PREPARED BY ARC ION PLATING

在不同偏压下用电弧离子镀沉积TiN薄膜,采用扫描电子显微镜(SEM)观察薄膜表面大颗粒污染情况,并分析偏压对大颗粒的影响。结果表明,偏压对大颗粒的影响主要来自电场的排斥作用。直流偏压下,等离子体鞘层基本稳定,电子对大颗粒表面充电能力很弱,而脉冲偏压下,由于鞘层厚度不断变化,大颗粒不断进出于鞘层,电子对大颗粒表面的充电能力强,使其所带负电荷明显增多,受到基体的排斥力变大,大颗粒不易沉积到基体而使薄膜形貌得到有效改善。

This paper studies the mechanism of macroparticles(MPs) contamination of TiN films obtained by arc ion plating(AIP) under different biases modes. The effect of bias has been analyzed from the viewpoint of plasma physics. It is shown that MPs are affected by bias through the repulsive force from the negatively biased substrate. MPs are easily charged by electrons under pulsed bias because they repeatedly move in and out of the oscillating plasma sheath. In dc bias, the plasma sheath is almost stable and its charging effect is weak. Thus the repulsive force from the substrate under pulsed biases is higher than that under dc ones, resulting in obvious reduction of the MPs amount.