AlN隔离层生长时间对AlGaN/AlN/GaN HEMT材料电学性能的影响

Influence of Growth Time of AlN Interfacial Layer on Electrical Properties of AlGaN/AlN/GaN HEMT Materials

利用金属有机化学气相沉积(MOCVD)设备,在蓝宝石(0001)面上外延不同生长时间AlN隔离层的AlxGa1-xN/AlN/GaN结构的高电子迁移率的晶体管(HEMT),研究了AlN隔离层厚度对HEMT材料电学性能的影响。研究发现采用脉冲法外延(PALE)技术生长AlN隔离层的时间为12 s(1 nm左右)时,HEMT材料的方块电阻最小,电子迁移率为1 500 cm2·V-1·s-1,二维电子气(2DEG)浓度为1.16×1013cm-2。AFM测试结果表明,一定厚度范围内的AlN隔离层并不会对材料的表面形貌产生重大的影响。HRXRD测试结果表明,AlGaN/AlN/GaN具有好的异质结界面。

AlGaN/AlN/GaN HEMT structures were grown on sapphire substrate by MOCVD with dif-ferent AlN growing time, and the influence of AlN thickness on electrical properties was investiga-ted. When AlN growth time is about 12 s corresponding to the AlN thickness of 1 ~1. 5 nm, the sample has the best performance of electrical properties with the lowest sheet resistance of 359 Ω· sq-1 , the highest 2DEG concentration of 1. 16í1013 cm-2 , and a high 2DEG mobility of 1 500 cm2 · V-1 ·s-1 . AFM results indicate that AlN layer within a certain thickness range has little influence on the surface morphology. HRXRD results show that AlGaN/AlN/GaN HEMT has a good hetero-structure interface.