本論文探討製作於氮化鎵基板以及矽基板之氮化鎵功率元件，根據不同之基板類型，分成以下兩個部分討論: (1)整合垂直式的蕭特基二極體與水平式的高電子遷移率電晶體於氮化鎵基板之研究；(2)具挖洞式歐姆接觸的高電子遷移率電晶體於矽基板之研究。本研究包含元件的設計、TCAD模擬、製作與電性分析。 對於氮化鎵基板之功率元件，藉由氮離子佈植形成電流阻擋層，製作具有圓形和環形通道的垂直式氮化鎵蕭特基二極體，佈植能量及劑量分別為150/100 keV與1 × 10^15 cm^-2；電流阻擋層能夠將通道與高臺(mesa)邊緣分離，減少蝕刻損傷造成的影響以及反向偏壓下的邊緣效應，從而降低元件的漏電流並且提高崩潰電壓。此外，環形通道可以形成電流擴散，因此相較於具有圓形通道之蕭特基二極體，具有環形通道之蕭特基二極體的導通電阻會比較小，其崩潰電壓以及導通電阻分別為956 V與1.13 mΩ∙cm^2，巴利加優值（Baliga figure of merit, BFOM）為808.79 MW/cm^2。另外，水平式的氮化鎵/氮化鋁鎵高電子遷移率電晶體也可以與垂直式GaN蕭特基二極體一起同時完成，達成單片整合之設計。氮化鎵/氮化鋁鎵高電子遷移率電晶體的導通電阻與飽和電流分別為8.5 Ω‧mm (在VGS = 0 V，VDS = 0.2 V的條件下)與588.4 mA/mm (在VGS = 2 V，VDS = 10 V的條件下)。 對於矽基板之功率元件，藉由在歐姆接觸區域進行不同圖形與不同深度的挖洞，製作具有挖洞式歐姆接觸的氮化鎵/氮化鋁鎵高電子遷移率電晶體。在挖洞深度以及挖洞圖形為5.5 nm與1/3/5 μm的條件下，其特徵接觸電阻為7.1 × 10-7 Ω∙cm^2，大約比傳統無挖洞之歐姆接觸低一個數量級；並以此條件製作具挖洞式歐姆接觸之高電子遷移率電晶體，其導通電阻為14.6 Ω‧mm (在VGS = 0 V，VDS = 0.2 V的條件下)，比傳統HEMT小了約11%。 ;In this study, the GaN power devices fabricated on GaN substrates and silicon substrates are discussed. According to different substrate types, it is divided into the following two parts for discussion: (1) Integrating vertical Schottky diodes (SBDs) and lateral AlGaN/GaN high-electron-mobility transistors (HEMTs) on GaN substrates; (2) HEMTs with recessed ohmic contacts on silicon substrates. For the devices on GaN substrates, vertical SBDs using nitrogen ion implantation to form the circle and donut channels are proposed. Nitrogen ion with a energy of 100/150 keV and dose of 1 × 10^15 cm^-2 is used to form a current blocking layer to separate the channel from the mesa edge to reduce the etching damage and edge effect under reverse bias. The leakage current is reduced in the SBD with the donut channel thus improve the breakdown voltage. The specific differential ON-resistance (diff. RON, sp) is also improved in the SBD with a donut channel due to the wider current spreading than that in the SBD with a circle channel. A GaN SBD with the 2 μm donut channel and floating metal ring shows the diff. RON,sp of 1.13 mΩ∙cm^2 and the breakdown voltage of 956 V, with the Baliga’s Figure-Of-Merit (BFOM) of 808.79 MW/cm^2. In addition, AlGaN/GaN HEMTs can be fabricated simultaneously with vertical GaN SBDs to achieve monolithic integration. The on-resistance and saturation current of AlGaN/GaN HEMTs are 8.5 Ω‧mm (at VGS = 0 V, VDS = 0.2 V) and 588.4 mA/mm (at VGS = 2 V, VDS = 10 V) respectively. For the devices on silicon substrates, AlGaN/GaN HEMTs with various recessed depths and recessed patterns in the ohmic region are investigated. As the recessed depth and recessed pattern is 5.5 nm and 1/3/5 μm, the specific contact resistivity of 7.1 × 10-7 Ω∙cm^2 is achieved, which is about an order of magnitude lower than that of traditional fabrication strategy without recessed. The recessed ohmic contact HEMT (ROC HEMT) exhibits the on-resistance of 14.6 Ω‧mm (at VGS = 0 V and VDS = 0.2 V), which is 11 % lower than that of the conventional HEMT.
