Characterization of Different Technologies of GaN HEMTs of 0,15 μm Ultra-Short Gate Length: Identification of Traps Using TCAD Based 2D Physics-based Simulation

In this paper, we compare to different technologies (A and B) of 0.15-$\mu$m ultra-short gate length GaN HEMT devices using drain lag and gate lag measurements. A low frequency (LF) S-parameters measurements was also performed for different chuck temperatures ranging from 25circC and 100circC. The leakage current which was measured before and after S-parameters measurements for both technologies was lower than 100 $\mu$A/mm. In addition, a complete study has been performed to determine the exact location of the traps existing in technology A using TCAD based 2D physics-based simulation. Thus, the model parameters have been tuned to fit the dc simulation with the measured I-V characteristics at 25circC. This allows to estimate the concentration of traps (NT) present in the device at 25 °c. Knowing the trap energy level extracted using LF S-parameters measurements, TCAD physics-based simulations are performed at various temperatures in order to extract the low frequency Y22 admittance parameter. For technology A, TCAD simulation demonstrate that the concentration of traps increases when the temperature increases. Simulation results are in good agreements with the measurements and assume that the location of traps was in the buffer region, with an activation energy Ea=0.47eV and cross section around $6\times 10^{-16}cm^{2}$.