利用傾斜式陽極製作高功率氮化鋁鎵氮化鎵蕭基二極體

Abstract

近年來，高功率元件不斷的在新世代應用崛起。氮化鎵功率元件更在市場供需中顯現了相當巨大的利潤。在本論文中，我們展現了高崩潰電壓、高操作輸出電流、低導通電阻的氮化鎵氮化鋁鎵異質接面結構蕭基二極體的設計。 傾斜式陽極蕭基二極體中，極化效應在氮化鋁鎵氮化鎵介面附近會感應載子形成高電子濃度及高遷移率的二維電子氣體通道，因而降低導通電阻(Ron)。 在元件結構中，我們利用場效電板技術分散蕭基接觸邊緣的電場，並藉由SILVACO軟體模擬元件內部電場分布，因此而驗證傾斜式電板技術為有效方式改善特性。 當使用高載子濃度基板時，導通電阻會低於1V，而導通電阻係數為1.25×10-3 Ω•cm2. 當使用厚緩衝氮化鎵層的基板時，最高崩潰電壓發生於陰陽極間距25μm的元件，為820V，而評量因子則為1.1×107 W/cm2。 在此篇論文中，我們專注於設計並製作高功率氮化鎵蕭基二極體。最後，我們在此篇研究展示了高崩潰、高輸出電流、低導通電壓的氮化鋁鎵氮化鎵蕭基二極體。

Recently, high power devices have expanded into a new generation of applications. Among various devices, GaN power electronics have demonstrated a high profit gaining in current market. In this study, we have high breakdown voltage, high operation current, and low turn-on voltage AlGaN/GaN heterostructure Schottky barrier diodes design. For our slated Schottky anode SBDs, the polarization will induce charges to form high electron concentration and high mobility 2DEG channel at AlGaN/GaN interface, reducing the on-state resistance (Ron). For device structure, we use field plate technique to disperse the electric field at the Schottky contact edge and use SILVACO to simulate the electric field distribution in the devices, to verify the recessed slanted field plate is effective for enhancement. For high carrier concentration substrates, the turn-on voltage is lower than 1V, and the specific on-resistance is 1.25×10-3 Ω•cm2. For thick-GaN-buffer substrates, the highest breakdown voltage is 820V for A-C spacing 25μm devices, and the figure of merit is 1.1×107 W/cm2. In this study, we focused on high performance GaN-based Schottky barrier diode design and fabrication. High breakdown voltage, high operating current, and low turn-on voltage AlGaN/GaN Schottky barrier diodes were demonstrated in this work.