Title :
MOCVD grown AlGaN/AlN/GaN HEMT structure with compositionally step-graded AlGaN barrier layer
Author :
Ma, Zhiyong ; Wang, Xiaoliang ; Hu, Guoxin ; Ran, Junxue ; Wang, Xinhua ; Wang, Baozhu ; Luo, Weijun ; Li, Jianpin
Author_Institution :
Inst. of Semicond., Chinese Acad. of Sci., Beijing
Abstract :
Unintentionally doped AlGaN/AlN/GaN high electron mobility transistor (HEMT) structures with compositionally step-graded AlGaN barrier layer were grown on sapphire substrates by metalorganic chemical vapor deposition (MOCVD). The HEMT structure exhibited typical two-dimensional electron gas (2DEG) mobility of 1600cm2/Vs at room temperature and 6412cm2/Vs at 79K with almost equal 2DEG concentration of 1.0times1013/cm2. The 50mm HEMT wafer exhibited an average sheet resistance of 318.0Omega/square, with a good resistance uniformity of 0.89%. Atomic force microscopy (AFM) measurements revealed a smooth AlGaN surface with root-mean-square roughness (RMS) of 0.199nm and 0.295nm for scan area of 2mumtimes2mum and 5mumtimes5mum, respectively. A combined using of compositionally step-graded AlGaN barrier structure and AlN interlayer results in the high electrical performance and smooth surface of this heterostructure
Keywords :
III-V semiconductors; MOCVD; aluminium compounds; atomic force microscopy; gallium compounds; high electron mobility transistors; sapphire; semiconductor growth; surface roughness; surface structure; two-dimensional electron gas; wide band gap semiconductors; 0.199 nm; 0.295 nm; 2 micron; 2D electron gas mobility; 2DEG mobility; 5 micron; 50 mm; 79 K; AFM; AlGaN; AlGaN barrier layer; AlGaN/AlN/GaN HEMT structure; AlGaN/AlN/GaN high electron mobility transistor structures; AlN; AlN interlayer; GaN; HEMT wafer; MOCVD; atomic force microscopy; metalorganic chemical vapor deposition; root-mean-square roughness; sapphire substrates; sheet resistance; Aluminum gallium nitride; Atomic force microscopy; Atomic measurements; Force measurement; Gallium nitride; HEMTs; MOCVD; Rough surfaces; Surface resistance; Surface roughness;
Conference_Titel :
Solid-State and Integrated Circuit Technology, 2006. ICSICT '06. 8th International Conference on
Conference_Location :
Shanghai
Print_ISBN :
1-4244-0160-7
Electronic_ISBN :
1-4244-0161-5
DOI :
10.1109/ICSICT.2006.306571
