Simulation of the Effect of GaN Buffer Layer Doped with Iron Fe and Carbon C on the DC Static Characteristics of Normally Open HEMT AlGaN/AlN/GaN Transistor

In this paper, we investigated the influence of doping a GaN buffer with iron Fe and carbon C on the static characteristics of DC normally open HEMT AlGaN/AlN /GaN transistors, as well as on their high-frequency RF characteristics. The simulation showed that the high-frequency characteristics of the transistor in which the buffer layer is not doped with iron or carbon changed little when the buffer is doped with iron or carbon, up to concentrations of 5 • 1017 (cm-3). A little change has occurred at extremely high concentrations 1 • 1018, 1 • 1019 (cm-3). A comparison of the simulation results for a buffer doped with iron and carbon shows that the effect of pushing the current from the depth of the buffer to the channel region is most pronounced when the buffer is doped with carbon. Thus, at a concentration of 1 • 1018 (cm-3) doping of the buffer with carbon, the depth of current penetration into the buffer decreases to a value of 0.10 mkm, with a buffer thickness of 2.00 mkm.