Title :
High-Current-Gain Direct-Growth GaN/InGaN Double Heterojunction Bipolar Transistors
Author :
Lee, Yi-Che ; Zhang, Yun ; Kim, Hee-Jin ; Choi, Suk ; Lochner, Zachary ; Dupuis, Russell D. ; Ryou, Jae-Hyun ; Shen, Shyh-Chiang
Author_Institution :
Sch. of Electr. & Comput. Eng., Georgia Inst. of Technol., Atlanta, GA, USA
Abstract :
We report high-current-gain n-p-n GaN/InGaN double-heterojunction bipolar transistors (DHBTs) using a direct-growth fabrication processing approach. The impact of the indium composition in the base layer was studied, and a burn-in effect using a constant-base-current stressing method was observed. We found that DHBTs with higher indium composition in the InGaN base layer may help reduce the base resistance and lower the surface recombination current but may result in higher bulk recombination current. A device burn-in effect was also studied. The postprocessing current stressing step helps increase free-hole concentration in the base, reduce the bulk recombination current, and enhance the current gain. As a result, a direct-growth GaN/In0.03Ga0.97N DHBT with a peak current gain of 105 and a collector current density > 6.5 kA/cm2 was demonstrated on a sapphire substrate.
Keywords :
III-V semiconductors; current density; gallium compounds; heterojunction bipolar transistors; indium compounds; p-n heterojunctions; sapphire; GaN-InGaN; burn-in effect; constant-base-current stressing; direct-growth fabrication; double heterojunction bipolar transistor; free-hole concentration; high-current-gain n-p-n; sapphire substrate; surface recombination current; Double heterojunction bipolar transistors; Etching; Gallium nitride; Indium; Integrated circuits; Direct growth; GaN; InGaN; heterojunction bipolar transistors (HBTs);
Journal_Title :
Electron Devices, IEEE Transactions on
DOI :
10.1109/TED.2010.2064316
