Deep-Donor-Induced Suppression of Current Collapse in an AlGaN-GaN Heterojunction Structure Grown on Si

Taketoshi TANAKA
Norikazu ITO
Shinya TAKADO
Masaaki KUZUHARA
Ken NAKAHARA

Publication
IEICE TRANSACTIONS on Electronics   Vol.E103-C    No.4    pp.186-190
Publication Date: 2020/04/01
Publicized: 2019/10/11
Online ISSN: 1745-1353
DOI: 10.1587/transele.2019ECP5011
Type of Manuscript: PAPER
Category: Semiconductor Materials and Devices
Keyword: 
AlGaN/GaN HFETs,  deep donor,  deep acceptor,  GaN,  semi-insulating,  

Full Text: FreePDF

Summary: 
TCAD simulation was performed to investigate the material properties of an AlGaN/GaN structure in Deep Acceptor (DA)-rich and Deep Donor (DD)-rich GaN cases. DD-rich semi-insulating GaN generated a positively charged area thereof to prevent the electron concentration in 2DEG from decreasing, while a DA-rich counterpart caused electron depletion, which was the origin of the current collapse in AlGaN/GaN HFETs. These simulation results were well verified experimentally using three nitride samples including buffer-GaN layers with carbon concentration ([C]) of 5×1017, 5×1018, and 4×1019 cm-3. DD-rich behaviors were observed for the sample with [C]=4×1019 cm-3, and DD energy level EDD=0.6 eV was estimated by the Arrhenius plot of temperature-dependent IDS. This EDD value coincided with the previously estimated EDD. The backgate experiments revealed that these DD-rich semi-insulating GaN suppressed both current collapse and buffer leakage, thus providing characteristics desirable for practical usage.