- 學位論文
不同閘極材料薄膜材料電晶體之電性穩定度比較
Comparison of Stability on a-Si:H TFT using Various Gate Materials
摘要
液晶顯示元件的發展，也就是由被動式矩陣驅動向列型(TN)/超扭向型(STN-LCD )液晶顯示器，推向主動式矩陣驅動薄膜電晶體液晶顯示器，並更加發展至所謂的新世代的顯示器，像是有機電發光顯示器（Organic Electro luminesence；OEL）或有機發光二極體(Organic Light Emitting Display, OLED)。 本研究嘗試將傳統TFT非晶矽(α-Si)製程與COA(Color filter on Array)製程這兩種薄膜電晶體的金屬閘極作一可靠度的測試，比較不同閘極的電性的穩定性，在TFT的製程為達到增加開口率，金屬連線的線寬與膜厚相對縮小，在電晶體所承受相同的操作電壓，因為面積變小電流密度增加，而容易產生電子遷移的現象。 過去TFT電晶體閘極(Gate)與源極及汲極(Source&Drain)的金屬連線均使用鋁金屬材質當導線，因鋁金屬製程方式較為成熟且因為有較低的阻抗，此次COA製程改變閘極金屬材質使用銅(Cu)金屬，目的是為了改善TFT電晶體開關的特性，實驗時將比較兩種金屬在電子遷移（Electro-migration）過程中的特性，作此測試的條件會加高溫度使鋁銅的金屬導線高於正常的電流層次，當高密度的電流通電到金屬導線層上，並由加速溫度環境與室溫環境的結果比較來求出電子遷移的活化能，進而比較鋁銅材質閘極的耐久度，以及對a-Si:H/SiNx界面缺陷(Interface states)的產生與銅鋁金屬電極TFT的臨界電壓(Threshold Voltage)在高直流偏壓下(DC bias stress)發生偏移的行為進行分析與研究，藉此了解金屬電極的不同對TFT元件的影響與原因。
並列摘要
Liquid crystal display is driven by Twisted Nematic (TN)/ Super Twisted Nematic(STN) of passive matrix to thin-film transistor liquid crystal display driver of active matrix. Now we called new generation display as their development component and there was no difference in ITO of organic electronic light emitting display(OLED). We were testing the electrical stability on the metal gate of TFT amorphous silicon/ color filter on array(COA) process. To achieve the aperture ratio in TFT process, the critical dimension(CD) and film-thickness are relative narrow. Same operating voltage on the transistors, Small area because of the increased current density Occurred electron-migration. In the past, the source & drain of the metal connections were using aluminum as the wire, because it has lower resistance and well-developed skill. In the COA process this time, we changed the material from aluminum to Cu and we did the characteristic comparison of them. The condition was heightening the temperature caused metal showed higher current. Compared the high current connected on the metal layer with elevated temperature and the ambient room temperature is obtained the activation energy of electron mobility. We analysis and research their durability, produce the a-Si:H/SiNx of interface states and the threshold voltage at high DC stress cause shifted situation happened, we also know the effects of different materials.