Synthesis of Nano-Structured Anodic Oxides over Conductive Nitride Films by Anodic Oxidation

Abstract

This is a three-year project. This research implements our group』s previous experiences onsynthesis of thin films by combining physical vapor deposition and electrochemical anodic oxidation.Basically this project employs conductive nitride films including TiN (1st-year project), CrN (2nd-yearproject), and ZrN (3rd-year project) and then conducts anodic oxidation to synthesize high qualityfunctional oxide films with special microstructure/nanostructure or phase. The oxide films containTiOx, CrOx, ZrOx and related oxide films (M1M2Ox, M1: metal 1 form electrolyte, M2= Ti, Cr, or Zr).Since very few literature has been reported concerning such a duplex deposition technique (PVD andanodic oxidation), the idea of this project is original. Moreover, anodic oxidation exhibits manyadvantages over other deposition techniques, such as simple set-up, mass production feasibility, highquality films possessing crystalline phases, excellent adhesion, especially special microstructures. Thishas a great potential in industrial applications.In electrochemical anodic oxidation, process variables requiring careful control includeelectrolyte』s composition, concentration, and temperature, as well as input voltage, current, etc. Theset-up implements our group developed programs to control and monitor these variables. The filmsafter anodic oxidation will be characterized as follows:(1) appearance— by optical microscopy and SEM.(2) crystal structure/microstructures— phases investigated by XRD and GIXD (Grazing IncidenceX-ray Diffraction), microstructure by SEM (FE-SEM) and TEM(3) chemical states/composition profiles— chemical states by XPS (X-ray PhotoelectronSpectroscopy) and Raman spectroscopy, as well as composition profiles by AES (AugerElectron Spectroscopy).(4) properties— several important items including residual stress, adhesion, electrical and dielectricproperties, etc.The final goal is to tailor the structure of the anodic oxide films by analyzing the base nitride films,controlling variables in anodic oxidation, and investigating the resultant anodic oxide films. It is thenpossible to optimize the properties of the films.

本研究計畫為三年期，主要是結合過去本實驗室在物理氣相沉積與電化學陽極氧化製備功能性薄膜之研究基礎，在導電之氮化鈦(TiN-第一年期)、氮化鉻(CrN-第二年期)、氮化鋯(ZrN-第三年期)薄膜上進行陽極氧化，以製備高品質特殊微結構與奈米結構之功能性氧化膜，此氧化膜包括了鈦氧化物(TiOx)、鉻氧化物(CrOx)與鋯氧化物(ZrOx)以及相關之氧化膜(M1M2Ox, M1:metal 1 來自電解液, M2= Ti, Cr,或Zr)等。由於結合物理氣相沉積氮化物薄膜與陽極氧化製備氧化膜之文獻非常少見，本研究有學術之新穎性，又由於陽極氧化之裝置簡易、易量產、膜易形成結晶、附著性佳、高品質、特別是可形成其他製程所不易得到之微結構等特點，亦有相當大工業應用之潛力。進行電化學陽極氧化時，主要控制參數有電解液成分、濃度、溫度、輸入之電壓、電流等，配合本實驗室自行開發之程控軟體，控制與監測此些製程參數，經電化學陽極氧化後的試片，再分項分析其：1. 表面形貌— 以立體顯微鏡、光學顯微鏡及掃瞄式電子顯微鏡檢視。2. 結晶相/微結構— 使用 X 光繞射儀及低掠角X 光繞射儀分析結晶相，並輔以掃瞄式(含場發射式)與穿透式電子顯微鏡分析微結構。3. 化學狀態及成分分佈— 用 X 光光電子能譜儀與顯微拉曼光譜儀分析其化學組態、並以歐傑電子能譜儀分析組成縱深分佈。4. 特性分析— 包括應力、附著性與電性及介電等特性分析。最後綜合整理分析，以期經底材氮化物膜之分析、陽極氧化製程參數之控制、與陽極氧化膜之完整分析，可獲致高品質特殊結構之功能性或特殊化學組態之陽極氧化膜。