2015-06-012024-05-17https://scholars.lib.ntu.edu.tw/handle/123456789/691615摘要：GaN功率元件具有高耐壓以提供高電壓操作，快速的開關切換速度以適用於高頻開關切換，低導通電阻以利於大電流高功率密度應用等好處。在這幾年迅速竄起，有機會取代Si成為下一代功率元件半導體選擇。 在電特性上，GaN高電子遷移率電晶體(HEMT)除了面臨本身空乏型的操作機制以外，另一項令人詬病的問題是Current collapse的現象，Current collapse將造成元件電性衰退因而降低能量轉換效率。尤其在更高的工作電壓條件下，Current collapse的問題變得更為嚴重，影響元件穩定度，這是功率元件要迫切解決的問題。 過去兩年來，我們成功的展示了p型GaN覆蓋層之E-mode HEMT，本計劃將與曜輝光電合作，探討E-mode HEMT在current collapse的機制，由於我們的p型GaN覆蓋層使得閘極下方形成空乏區，減少穿隧漏電流，降低電晶體表面缺陷抓住電子而空乏掉二維電子氣體的機會，預期我們所設計的p型GaN覆蓋層HEMT在Current collapse的抑制上會有顯著的效果。 我們並結合MIS (Metal-insulator-semiconductor) 本身絕緣層結構結構於E-mode HEMT，來達成低閘極漏電流，高崩潰電壓以及較廣的閘極偏壓操作。我們將探討MIS結構與p型GaN覆蓋層的結合是否更能鈍化表面缺陷，抑制Current collapse，並研究不同元件結構，不同絕緣層材料，以及製程參數對抑制Current collapse的成效。 本計劃最終目的是藉由current collapse及漏電流的抑制，使得我們的結構能幫助曜輝光電進入量產。 <br> Abstract: GaN power devices have the advantages of high-voltage, high-current operation, high-speed switching and low-channel resistance, making them ideal candidates for replacing Si for next-generation power semiconductor. In electrical characteristics, other than issues of their intrinsic depletion-mode property, GaN HEMTs (high-electron mobility transistors) suffer from a phenomenon called current collapse. Current collapse will degrade the electrical performance and power switching efficiency. Especially under a high-voltage operation, the problem becomes more severe, affecting the device stability. In the past two years, we successfully demonstrate E-mode HEMTs by incorporating a p-GaN cap layer. The current proposal is to collaborate with Neoton Optoelectronic to explore the mechanisms of current collapse in E-mode HEMTs. Because of the depleted channel and surface in the p-GaN/AlGaN/2 DEG GaN channel, the leakage current has been demonstrated to be significantly depressed. The depleted surface states have resulted in, as we anticipate, the improvement of current collapses with our p-GaN cap layer E-mode HEMTs. Furthermore, we will apply MIS (Metal-insulator-semiconductor) structure to our device. The semiconductor surface will be further passivated so that less leakage current, higher breakdown voltage and less current collapse can be achieved. We will study the effect based on different MIS structure, different dielectric coatings and process conditions. The final goal is to mitigate current collapse and the leakage current of E-mode HEMTs so that the devices can be used for mass-production.功率元件氮化鎵高電子遷移電晶體power deviceGaNHEMT