國立臺灣大學電子工程學研究所胡振國2006-07-262018-07-102006-07-262018-07-102004-07-31http://ntur.lib.ntu.edu.tw//handle/246246/20003本年度之主要研究成果可分成四大項，分別為生長溫度對超薄氧化層晶圓應力分布影響、生長壓力對超薄氧化層晶圓應力分布影響、切割對超薄氧化層晶圓元件之影響、及應力下生長高品質超薄閘極氧化層技術。將晶圓整片生長超薄氧化層，做成MOS電容元件結構，將各元件之正偏壓基板注入(substrate injection)飽和電流對負偏壓閘極注入(gate injection)漏電流作圖，其中負偏壓閘極注入漏電流的大小與氧化層厚度相關，而正偏壓基板注入飽和電流大小則受控於少數載子濃度之有限供應，而氧化生長程度不同引起之基板表面應力大小可明顯由該飽和電流大小反應出。本研究發現在低溫下氧化層厚度極度不均勻，但基板表面受生長破壞引起之缺陷及應力較不嚴重；反之，當溫度升高後，氧化層厚度變厚，閘極注入電流趨於均勻，但是氧化引起之晶圓表面則受到不同程度之破壞，因此基板注入飽和電流分布呈現漸嚴重之不均勻。將壓力做改變，發現低壓生長情形類似低溫生長，而高壓生長則類似於高溫生長。此外，實驗發現當晶圓經切割後，在沿切割線附近之MOS元件其特性明顯易受影響，包括閘極注入漏流變小、基板注入飽和電流變大、及電容值變小，相當於氧化層厚度等效變厚，而遠離切割線之元件則沒有明顯變化，顯示切割會對晶圓內存應力進行釋放或轉移，造成電特性改變，此發現相當前瞻重要，值得進一部探討。本研究同時提出一前瞻性之技術，將晶圓於受應力下予以液相陽極氧化生長氧化層，使矽基板原子間隔變大而可以和SiO2之晶格匹配，進而使SiO2/Si界面較完整，結果發現相對於無施加應力下所生長之氧化層呈現較小之漏流，及較佳之穩定性，對現今超薄氧化層生長技術提供甚佳之參考。There are four major topics investigated in this work, i.e., the effect of oxidation temperature on the stress variation of ultra-thin oxides, the effect of pressure on the stress variation of ultra-thin oxides, the effect of scribing across the wafer on the reliability of MOS devices with ultra-thin gate oxides, and the novel technology of oxidation under stress. The wafer was oxidized in a rapid thermal process system and then MOS structures are performed after Al metallization and patterning. The positively biased substrate injection current versus the negatively biased gate injection current was plotted to find the stress characteristics. Generally, the positively biased substrate injection current will be saturated due to the insufficient supply of minority carriers. Oxidation will cause the damage of the substrate surface and therefore introduce defects or stress on the substrate surface. That will affect the above saturation current significantly. So, stress characteristics can be observed via the analysis of substrate injection saturation current behavior. It was found that for low temperature oxidation, the oxide thickness is non-uniform but the damage of surface is small. However, when the temperature is raised, the oxide thickness becomes large that makes the gate injection currents become uniform. The oxidation-induced damage to substrate surface is more severe than low temperature, so the positively bias substrate injection currents become non-uniform. For the issue of pressure, it was found that the effect of low pressure is similar to low temperature, while high pressure is vise versa. For the effect of scribing, it was found that the MOS devices located along the scribing line are more easy to be affected by scribing than those faraway from the line. The effects include the reduction of gate injection current, the increase of substrate injection current, and the reduction of accumulation capacitance. It is important to the consideration of package and is worthy of further investigation. In this work, a novel technology of oxidation under mechanical stress is proposed. The wafer was mechanically stressed during anodization to enlarge the lattice constant of Si to match that of SiO2 so that the SiO2/Si interface will become more perfect than without. It was found that the stressed oxidation samples exhibit less leakage and better reliability than those without. It is interesting for the oxidation engineering in preparing ultra-thin gate oxides.application/pdf414311 bytesapplication/pdfzh-TW國立臺灣大學電子工程學研究所超薄氧化層應力分析溫度效應壓力效應切割效應應力生長技術temperature effectpressure effectscribing effectstressed oxidation technologyreporthttp://ntur.lib.ntu.edu.tw/bitstream/246246/20003/1/922215E002005.pdf