Heterojunction bipolar transistors and ultraviolet-light-emitting diodes based in the III-nitride material system grown by metalorganic chemical vapor deposition

Metalorganic chemical vapor deposition;Heterojunction bipolar transistor;III-nitrides;Gallium nitride;Ultraviolet laser diode

Lochner, Zachary M. ; Dupuis, Russell D. Electrical and Computer Engineering Yoder, Paul D. Vogel, Eric Cai, Wenshan Shen, Shyh-Chiang ; Dupuis, Russell D.

University:Georgia Institute of Technology

Department:Electrical and Computer Engineering

关键词: Metalorganic chemical vapor deposition;    Heterojunction bipolar transistor;    III-nitrides;    Gallium nitride;    Ultraviolet laser diode;   

Others  :  https://smartech.gatech.edu/bitstream/1853/49032/1/LOCHNER-DISSERTATION-2013.pdf

美国|英语

来源: SMARTech Repository

【 摘 要 】

The material and device characteristics of InGaN/GaN heterojunction bipolar transistors (HBTs) grown by metalorganic chemical vapor deposition are examined.Two structures grown on sapphire with different p-InxGa1-xN base-region compositions, xIn = 0.03 and 0.05, are presented in a comparative study. In a second experiment, NpN-GaN/InGaN/GaN HBTs are grown and fabricated on free-standing GaN (FS-GaN) and sapphire substrates to investigate the effect of dislocations on III-nitride HBT epitaxial structures. The performance characteristics of HBTs on FS-GaN with a 20×20 m2 emitter area exhibit a maximum collector-current density of ~12.3 kA/cm2, a D.C. current gain of ~90, and a maximum differential gain of ~120 without surface passivation. For the development of deep-ultraviolet optoelectronics, several various structures of optically-pumped lasers at 257, 246, and 243 nm are demonstrated on (0001) AlN substrates.The threshold-power density at room temperature was reduced to as low as 297 kW/cm2. The dominating polarization was measured to be transverse electric in all cases. InAlN material was developed to provide lattice matched, high-bandgap energy cladding layers for a III-N UV laser structure. This would alleviate strain and dislocation formation in the structure, and also mitigate the polarization charge. However, a gallium auto-doping mechanism was encountered which prevents the growth of pure ternary InAlN, resulting instead in quaternary InAlGaN. This phenomenon is quantitatively examined and its source is explored.