高效能氮化物功率半導體元件

High Performance Nitride-Based Power Semiconductor Devices

林于軒(Yu-Syuan Lin)

指導教授 ： 徐碩鴻

國立清華大學/電機資訊學院/電子工程研究所/博士(2009年)

摘要

氮化鎵(GaN)以及由其他三族元素如鎵(Gallium)、鋁(Aluminum)、銦(Indium)、與氮(Nitrogen)組成的相關氮化物，由於其獨特的材料特性，例如寬能隙(Eg= 3.4 eV)、較高的崩潰電場(> 3 MV/cm)、高電子飽和速度(~ 3×107cm/s)及電子遷移率(> 1000cm2 / V-s)、良好的熱穩定性、以及相當高的極化效應(polarization effect)，在光電、通訊、以及高功率電子上已經有相當廣泛的研究與應用。本篇論文主要在於利用氮化鎵優越的材料特性設計及製造出具有高速及高功率之氮化鎵電晶體。在第三章中我們提出square-gate佈局應用在藍寶石(sapphire)基板及矽(Silicon)基板上，並製造出耐壓能力高於650V及540V且具有低導通電阻的AlGaN/GaN高電子遷移率電晶體(high electron mobility transistor, HEMT)。第四章主要在描述氮化鎵蕭特基二極體的設計及製造方法，所製造出的元件崩潰電壓最高可以達到700V，另外我們也使用指叉式的佈局設計，以達到高電流及高切換速率等特性。第五章我們提出oxide-filled的絕緣方式，以降低元件在off-state狀態的漏電流，結果顯示藉由此方法漏電流可以大幅降低至10-9A/mm。 論文最後我們發表了第一顆具有高電流密度的銦化鎵(InN)電晶體，其操作電流可高達530mA/mm，結果顯示銦化鎵及相關化合物在未來的高速及高頻元件應用上，具有相當高的發展潛力。

關鍵字

氮化鎵 ； 氮鋁化鎵 ； 氮化物 ； 高功率半導體

並列摘要

GaN-based semiconductor materials play an important role for high power and high speed device and circuit applications. Compared with Si, GaN has higher breakdown field and electron drift velocity, which make GaN-based devices an excellent candidate for such applications. This dissertation focuses on the design and fabrication of high performance GaN-based devices with high breakdown voltage, high operation speed and low on resistance. In this study, we realize high voltage AlGaN/GaN HEMTs with low on-resistance and over 600 V breakdown voltage. We also demonstrate 700-V AlGaN/GaN Schottky diodes which show a fast reverse recovery of only 15 ns. In addition, we propose a new process flow for GaN HEMTs to minimize the off-state leakage. The oxide-filled isolation followed by post-gate treatment reduces the off-state leakage by more than three orders of magnitude compared with conventional devices. An off-state drain leakage current smaller than 1e-9 A/mm and an excellent ON/OFF current ratio up to 1.5e8 can be achieved. We also demonstrate the first InN/AlN HFET with gate-controllable characteristics. Owning to the high sheet carrier density, a high current density up to ~530 mA/mm is achieved in a device with a 5-um gate length and a width of 100um, which is much higher than that in conventional GaN-based devices.

並列關鍵字

GaN ； AlGaN ； Nitride-Based ； High Voltage ； High Current Density ； Power Semiconductor

參考文獻

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