節能工程是目前全球工業發展的訴求，為此使用氮化鎵材料取代傳統矽基材，以製作具有大崩潰電壓、大電流傳導以及快速切換特性的蕭基二極體，預期可降低電源供應器、電動車以及功率因子校正器之功率損耗。本研究使用成長於藍寶石基板上之氮化鋁鎵/氮化鎵異質接面與高阻值緩衝層磊晶結構，以指叉型並聯元件設計，成功地降低蕭基二極體的串聯阻值，實現1.5 V下9.5 A的大電流特性。為了進一步降低蕭基二極體的順向導通電壓。本研究亦開發了陽極蝕刻製程技術並探討不同蝕刻深度對元件特性的影響，其中陽極蝕刻深度超過二維電子氣的元件，在經過製程的調整改善後，可成功將理想因子從2.94降至1.82，並將元件導通電壓由1.2 V降低至0.5 V。利用此製程條件，可在6吋矽基板上製作出導通電壓為0.5 V，與1.5 V下順偏電流為4.3 A的大電流元件，其單根指叉元件的崩潰電壓可達424 V。 此外，利用總長40 mm的元件，在相同元件面積且不影響直流特性下，本研究設計不同的陽極型態以探討蕭基接面對電容及逆向回復特性的影響，成功地藉由陽極蝕刻的方式，降低元件逆向回復時間至25 ns，比起無蝕刻的蕭基二極體，降低達19.4 %，減少逆向回復電荷多達24 %。 Recently, energy saving has become increasingly important in worldwide industrial development. GaN-based Schottky barrier diodes (SBDs) with high breakdown voltage, high current conduction and highly efficient switching characteristics have been proposed to be a promising electronic component for energy-efficient power supplies, electric vehicles and power factor correction circuits, compared to the traditional Silicon devices. In this study, AlGaN/GaN heterostructures with a highly resistive buffer layer on sapphire substrates are used to develop multi-finger devices for high current operation. GaN SBDs with forward current as high as 9.5 A @ 1.5 V have been successfully demonstrated on devices with 320 mm-long finger. To further reduce the turn on voltage of SBDs, an anode recess technology is developed and used to explore the characteristics of devices with different recessed depth. The ideality factor of SBDs with an etch depth that passes the position of the two dimensional electron gas (2DEG) is reduced from 2.94 to 1.82 by process modification. The turn on voltage has also been reduced from 1.2 V of the non-recessed SBDs to 0.5 V of the SBDs with an etch depth passing the 2DEG. Thus, 100 mm SBDs with high current conduction of 4.3 A @ 1.5 V have been demonstrated on 6 inch silicon substrates successfully. Breakdown voltage of 424 V for the single finger SBDs with anode width of 1 mm has also be achieved. In addition, SBDs with 40 mm-long fingers are prepared to study the junction capacitance and reverse recovery time of devices with different anode geometry. Reverse recovery time of 25 ns is obtained by using the anode recess technique. Comparing with SBDs without anode recess, the recovery time is reduced by 19.4 % and the recovery stored charge is also reduced by 24 %.
