Improved DC and RF Characteristics of GaN-Based Double-Channel HEMTs by Ultra-Thin AlN Back Barrier Layer
Year: 2024
Type: article
Abstract: In order to improve the off-state and breakdown characteristics of double-channel GaN HEMTs, an ultra-thin barrier layer was chosen as the second barrier layer. The strongly polarized and ultra-thin AlN sub-barrier and the InAlN sub-barrier are great candidates. In this article, the two epitaxial structures, AlGaN/GaN/AlN/GaN (sub-AlN) HEMTs and AlGaN/GaN/InAlN/GaN (sub-InAlN) HEMTs, were compared to select a more suitable sub-barrier layer. Through TEM images of the InAlN barrier layer, the segregation of In components can be seen, which decreases the mobility of the second channel. Thus, the sub-AlN HEMTs have a higher output current density and transconductance than those of the sub-InAlN HEMTs. Because the high-quality AlN barrier layer shields the gate leakage current, a 294 V breakdown voltage was achieved by the sub-AlN HEMTs, which is higher than the 121 V of the sub-InAlN HEMTs. The current gain cut-off frequency (fT) and maximum oscillation frequency (fmax) of the sub-AlN HEMTs are higher than that of the sub-InAlN HEMTs from low to high bias voltage. The power-added efficiency (PAE) and output power density (Pout) of the sub-AlN HEMTs are 57% and 11.3 W/mm at 3.6 GHz and 50 V of drain voltage (Vd), respectively. For the sub-InAlN HEMTs, the PAE and Pout are 41.4% and 8.69 W/mm, because of the worse drain lag ratio. Thus, the Pout of the sub-AlN HEMTs is higher than that of the sub-InAlN HEMTs.
Source: Micromachines
DOI: 10.3390/mi15101220
Institutions: Xidian University, ZTE (China)
Language: English
Subfield: Condensed Matter Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $2,955
Awards: G1071447927, G1126433943, G1220661308, G1263959120, G1402608621, G1523594171, G1874009790, G1993669081, G2308888990, G2374946727, G2408319543, G2773629504, G280019884, G2853487018, G290468435, G3030363, G3372063648, G3945857178, G4142207067, G461459989, G4877702549, G5065543443, G5207768585, G5373512620, G5536712496, G5599249283, G5752182232, G5968290882, G6184712203, G6224553135, G6258709031, G6377886921, G6557776826, G6587431094, G6642165711, G6924690327, G6950084816, G7008208132, G704711181, G7185126207, G7225868883, G7259361109, G7368592925, G7441994562, G7496257037, G7855967326, G7960803661, G8087264447, G8265600006, G866944886, G939500548
OpenAlex ID: W4402994399