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Deep-Donor-Induced Suppression of Current Collapse in an AlGaN-GaN Heterojunction Structure Grown on Si
IEICE TRANSACTIONS on Electronics
Publication Date: 2020/04/01
Online ISSN: 1745-1353
Type of Manuscript: PAPER
Category: Semiconductor Materials and Devices
AlGaN/GaN HFETs, deep donor, deep acceptor, GaN, semi-insulating,
Full Text: FreePDF
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.