Study on surface barrier height in nitride-based semiconductors

2014 Fiscal Year Final Research Report

• Project/Area Number: 24560399
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Electron device/Electronic equipment
• Research Institution: University of Fukui
• Principal Investigator: TOKUDA Hirokuni 福井大学, 工学(系)研究科(研究院), 特命助教 (10625932)
• Co-Investigator(Kenkyū-buntansha): KUZUHARA Masaaki 福井大学, 大学院工学研究科, 教授 (20377469)
• Project Period (FY): 2012-04-01 – 2015-03-31
• Keywords: AlGaN/GaN / heterostructure / barrier height / sheet electron density / mobility / Hall effect measurement

Outline of Final Research Achievements

We found that sheet electron density and electron mobility were increased in AlGaN/GaN heterostructures deposited with Ni/Al by annealing in vacuum. By optimizing the Ni/Al thickness, we achieved a room temperature mobility of 3050 cm2/Vs, which is the highest value ever reported for AlGaN/GaN heterostructures. To apply this technology for improving the device performance, we fabricated AlGaN/GaN HEMTs by placing vacuum annealed Ni/Al layers alongside the source electrode. The on-resistance between source and drain (Rds) was compared for with and without vacuum annealed Ni/Al layers. The results showed that Rds was reduced for the HEMTs with vacuum annealed Ni/Al layers, however, the amount of Rds reduction was much small than that was expected. Although the newly developed vacuum annealing technology can reduce the source resistance, the effect of the reduction is limited. There remains a challenge to study HEMTs’structure to which the vacuum annealing technology is applicable.

Free Research Field

半導体工学