| Autor: |
Ravikiran, L., Dharmarasu, N., Radhakrishnan, K., Agrawal, M., Yiding, Lin, Arulkumaran, S., Vicknesh, S., Ng, G. I. |
| Předmět: |
|
| Zdroj: |
Journal of Applied Physics; 1/14/2015, Vol. 117 Issue 2, p025301-1-025301-7, 7p, 1 Color Photograph, 1 Diagram, 3 Charts, 9 Graphs |
| Abstrakt: |
To improve the confinement of two-dimensional electron gas (2DEG) in AlGaN/GaN high electron mobility transistor (HEMT) heterostructures, AlGaN/GaN/AlGaN double heterojunction HEMT (DH-HEMT) heterostructures were grown using ammonia-MBE on 100-mm Si substrate. Prior to the growth, single heterojunction HEMT (SH-HEMT) and DH-HEMT heterostructures were simulated using Poisson-Schrödinger equations. From simulations, an AlGaN buffer with "Al" mole fraction of 10% in the DH-HEMT was identified to result in both higher 2DEG concentration (~1013cm2) and improved 2DEG confinement in the channel. Hence, this composition was considered for the growth of the buffer in the DH-HEMT heterostructure. Hall measurements showed a room temperature 2DEG mobility of 1510cm2/V.s and a sheet carrier concentration (ns) of 0.97×1013cm2 for the DH-HEMT structure, while they are 1310cm2/V.s and 1.09×1013cm2, respectively, for the SH-HEMT. Capacitance-voltage measurements confirmed the improvement in the confinement of 2DEG in the DH-HEMT heterostructure, which helped in the enhancement of its room temperature mobility. DH-HEMT showed 3 times higher buffer break-down voltage compared to SH-HEMT, while both devices showed almost similar drain current density. Small signal RF measurements on the DH-HEMT showed a unity currentgain cut-off frequency (fT) and maximum oscillation frequency (fmax) of 22 and 25 GHz, respectively. Thus, overall, DH-HEMT heterostructure was found to be advantageous due to its higher buffer break-down voltages compared to SH-HEMT heterostructure. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
|
