Sheu Gene, Song Yu-Lin, Susmitha Dupati, Issac Kutagulla, Mogarala Ramyasri
Department of Computer Science and Information Engineering, Asia University, Taichung 41354, Taiwan.
Department of Bioinformatics and Medical Engineering, Asia University, Taichung 41354, Taiwan.
Membranes (Basel). 2021 Nov 20;11(11):899. doi: 10.3390/membranes11110899.
This study presents an innovative, low-cost, mass-manufacturable ion implantation technique for converting thin film normally on AlGaN/GaN devices into normally off ones. Through TCAD (Technology Computer-Aided Design) simulations, we converted a calibrated normally on transistor into a normally off AlGaN/GaN transistor grown on a silicon <111> substrate using a nitrogen ion implantation energy of 300 keV, which shifted the bandgap from below to above the Fermi level. In addition, the threshold voltage (V) was adjusted by altering the nitrogen ion implantation dose. The normally off AlGaN/GaN device exhibited a breakdown voltage of 127.4 V at room temperature because of impact ionization, which showed a positive temperature coefficient of 3 × 10 K. In this study, the normally off AlGaN/GaN device exhibited an average drain current gain of 45.3%, which was confirmed through an analysis of transfer characteristics by changing the gate-to-source ramping. Accordingly, the proposed technique enabled the successful simulation of a 100-µm-wide device that can generate a saturation drain current of 1.4 A/mm at a gate-to-source voltage of 4 V, with a mobility of 1487 cmVs. The advantages of the proposed technique are summarized herein in terms of processing and performance.
本研究提出了一种创新的、低成本、可大规模制造的离子注入技术，用于将AlGaN/GaN薄膜常开器件转换为常关器件。通过技术计算机辅助设计（TCAD）模拟，我们使用300 keV的氮离子注入能量，将校准后的常开晶体管转换为生长在硅<111>衬底上的常关AlGaN/GaN晶体管，这使得带隙从费米能级以下转移到以上。此外，通过改变氮离子注入剂量来调整阈值电压（V）。由于碰撞电离，常关AlGaN/GaN器件在室温下表现出127.4 V的击穿电压，其正温度系数为3×10 K。在本研究中，常关AlGaN/GaN器件的平均漏极电流增益为45.3%，这通过改变栅源斜坡对传输特性的分析得到了证实。因此，所提出的技术成功模拟了一个100 µm宽的器件，该器件在4 V的栅源电压下可产生1.4 A/mm的饱和漏极电流，迁移率为1487 cm²/Vs。本文从工艺和性能方面总结了所提出技术的优势。
