Preparation of Heat-proof Thin Film Capacitor by Using Ta_2N Anodized Film

采用Ta_2N化合物膜阳极氧化层，可以成功地制备出高耐热性能的薄膜电容器。为了减小氧化层厚度，在较低的阳极氧化电压下制备了Ta2N阳极电容器，研究了热处理对Ta_2N电容器的介电常数、TCC和漏电流的影响。结果表明，在80V的阳极电压下制备的Ta_2N阳极电容器在400ﾟC热处理后仍几乎没有退化。为了探讨Ta_2N阳极电容器耐热性能的原因，进行了俄歇深度分析。发现在400ﾟC以下，由于Ta2N的热稳定性，氧从氧化层向母材的扩散被抑制。在450ﾟC以上观察到的电学性能退化与氧化物/母材和铝电极/氧化物界面的退化是一致的。还进一步减薄了氧化层厚度。结果表明，30V阳极氧化的Ta_2N电容器的耐热性能优于160V阳极氧化的Ta_2N电容器，前者的电容值是后者的3倍以上。

Thin film capacitors with high heat-proof properties can be successfully made by using an anodized layr of Ta_2N compound film. In order to reduce the oxide thickness, Ta_2N anodized capacitors are prepared at low anodization voltage, and effects of heat-treatment on tan delta, TCC and leakage current are studied. It is found that Ta_2N anodized capacitor prepared at a anodization voltage of 80V show little degradation even after heat-treatment of 400ﾟC.To investigate the reason of heat-proof property of Ta_2N anodized capacitor, Auger depth analysis was carried out. It is found that oxygen diffusion from oxide layr to base-metal is suppressed below 400ﾟC,because of the thermal stability of Ta_2N.The degradation of electrical properties observed above 450ﾟC is consistent with that at interfaces of oxide/base-metal and Al-electrode/oxide. Further reduction of oxide thickness was also carried out. It is found that Ta_2N capacitor anodized at 30V is superior in heat-proof property to Ta one anodized at 160V and the capacitance value for the former is more than three times for the latter.