Oxidation and Degradation of Nitride Films at High Temperature under Controlled Atmosphere and in Plasma Environment(I)

Abstract

This research is a three-year project. This research employing similar methodologyestablished previously for TiN and CrN films focuses on other binary and ternary nitridefilm system. The main object is to investigate the oxidation of nitride films at hightemperature under controlled atmosphere and also in plasma environment. Theoxidation-related properties will also be studied. At the first year AlN will be employed asthe research system. As for the second and the third year, more complex TiAlN and TiCNsystems are used. The films will be deposited by magnetron sputtering and cathodic arcplasma deposition onto silicon substrates.After the deposition, the films will be firstly annealed at high temperature undercontrolled atmosphere. The following gases contain (1) air (pO2=0.21 atm) (2) O2/N2 andO2/CO2 mixing gases (pO2 ranges from 1 atm to 10 -5 atm) (3) CO2/N2/H2 mixing gases(very low pO2, pO2 is a function of T). Quite different ratios of (pN2/pO2) and (pCO2/pO2)can then be varied. Plasma oxidation of the films will also be performed sequentially. Keycontrolling parameters are r.f. power and pO2. Other important parameters are temperatureand also oxidation time.The films after annealing will be characterized as follows:(1) appearance— by optical microscopy and SEM.(2) crystal structure/microstructures— phases investigated by XRD and GIXD (GrazingIncidence X-ray Diffraction), microstructure by SEM (FESEM) and TEM(3) chemical states/composition profiles— chemical states by XPS (X-ray PhotoelectronSpectroscopy) and composition profiles by AES (Auger Electron Spectroscopy) andSIMS (Second Ion Mass Spectroscopy).(4) thermal analysis— by thermogravimetric and thermal differential analyses, as well asdifferential scanning calorimetry (DSC).(5) mechanical/electrical properties— by micro- indentor and 4-point probe tester.The final goal is to tailor the surface structure of the films by controlling relatedthermodynamic and kinetic factors and then to relate the surface structure to the resultantmechanical and electrical properties. Afterwards engineering the surface structure couldpossibly optimize the properties of the films

本研究計畫為三年期，主要是以先前研究的氮化鈦與氮化鉻模式系統，所建立的研究方法擴大應用在其他功能性的氮化物鍍膜上。本研究主要是有系統地探討鍍膜在高溫控制氣氛下及電漿環境下之氧化，與其相關性質之影響。期經由此氧化結果之分析，除了可瞭解其氧化行為與機制外，更可積極地經由熱力學以及動力學參數的控制，進而調製氮化物的表面結構，從而改善鍍膜性質。第一年期主要是以二元的氮化鋁(AlN)做為研究對像、第二年起以三元之氮化鋁鈦(TiAlN)及第三年的氮碳化鈦(TiCN)鍍膜作為探究系統。控制氣氛退火所使用的氣體包含（1）空氣（pO2=0.21 atm）（2）氧氣/氮氣與氧氣/二氧化碳混合氣（pO2=1~10-5 atm）（3）二氧化碳/氮氣/氫氣之混合氣（極低氧分壓）。以調變相當不同程度的氧/氮分壓比值與氧/二氧化碳分壓比值。電漿氧化控制的主要參數則為射頻功率及氣體壓力等。其他主要實驗參數則是溫度與時間。經高溫控制氣氛退火及電漿氧化後的試片，則分項分析其：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 光光電子能譜分析化學組態、並以歐傑電子能譜儀及二次離子質譜儀分析組成縱深分佈。4. 熱分析— 使用熱重分析（TGA）、熱差分析儀（DTA）或示差掃瞄量熱法（DSC）分析。5. 機械性質與電性— 分別以微硬度儀與四點探針測試儀量測分析。最後綜合整理分析，以期經由控制氣氛退火及電漿氧化結果之瞭解，並探究其對機械與電學性質之影響，以進而調製鍍膜表面結構，以期使性質最佳化。