電極材料對陽極氧化法製備之五氧化二鉭薄膜

Abstract

本實驗嘗試在陽極氧化後的Ta2O5薄膜上鍍著Al與Cu等電極材料，以探討電極材料對電性之影響，Ta、Ti、Cr等擴散阻絕層材料亦被鍍著在Ta2O5與上電極之間，以研究其對電性之影響與阻絕擴散之效應。掃描式電子顯微鏡被用以觀察薄膜橫截面的形貌；歐傑能譜儀、能量散佈光譜儀則被用以研究其縱深成分分析；電性量測部份則包括漏電流、散逸因子與電容值。實驗結果顯示若以Al為上電極，鍍上Ti擴散阻絕層後亦有較小的漏電流密度，大約為10-10A/cm2，散逸因子約為0.017，其電容值19.6pF，介電常數為31.7。若以Cu為上電極，鍍上Ti擴散阻絕層後有蠻小的漏電流密度，大約為10-9A/cm2，散逸因子約為0.03，其電容值16.6pF，介電常數為26.7。鍍上Ti擴散阻絕層後的薄膜電容，對其漏電流與散逸因子有一定的改善，也較能阻止上電極的擴散。

In this work anodization process was applied to prepare tantalum oxide film and its electrical properties affected by the materials of top electrode were evaluated. Furthermore, various diffusion barrier metals were deposited in between the top electrode and oxide and their effects on electrical properties were also investigated. The scanning electron microscope (SEM) was adopted to reveal the cross-sectional structure of the specimens. The concentration depth-profile was investigated by Auger electron spectroscopy (AES) and energy dispersive spectrometer (EDS). Experimental results indicated that the specimens deposited Ti diffusion barrier has lower leakage current (10-10A/cm2) and dissipation factor (0.03). The Ti layer effectively inhibited the interdiffusion of the top electrode and oxide hence provided better electrical properties of the capacitor specimens.