On reduction of current leakage in GaN by carbon-doping

Abstract

Carbon-doping is proposed to reduce the dislocation-mediated leakage currents in the GaN buffer layers. GaN:C grown by metalorganic vapor phase epitaxy using propane shows excellent quality up to [C] = 6.7 × 1018 cm−3. Locally probing dislocations by surface scanning potential microscopy reveal a transition from mostly neutral or weakly charged regions to dominantly negatively charged regions relative to the surrounding area at high doping levels. A relation between leakage currents and the relative dislocation charge state exists. Minimum leakage current is achieved if the dominant charge state of dislocation regions becomes negative against the surrounding.

“Hole Redistribution” Model Explaining the Thermally Activated R ON Stress/Recovery Transients in Carbon-Doped AlGaN/GaN Power MIS-HEMTs

“…Indeed, C-related donors could actually be closer to EC or even be modelled as completely ionized doping, in agreement with recent hybridfunctional DFT calculations [14], [26]. Further, an experimental indication that C doping introduces donors besides acceptors is found in [27]. According to previous reports, for moderate C doping concentration (i.e., ≤10 18 cm −3 ) it is appropriate to model dopants as discrete point defects, whereas for concentrations of about (or higher than) 10 19 cm −3 it is more appropriate to use a defect-band model [28].…”

The Role of Carbon Doping on Breakdown, Current Collapse, and Dynamic On‐Resistance Recovery in AlGaN/GaN High Electron Mobility Transistors on Semi‐Insulating SiC Substrates

“…The choice of the C-doping model adopted in this work is justified by the fact that by adjusting the donor-acceptor auto-compensation ratio it is possible to accurately reproduce dynamic effects in different AlGaN/GaN power HEMTs [9]- [13]. Moreover, a higher donor concentration in C-doped GaN compared to the donor density measured in unintentionally doped samples was experimentally confirmed in [14], and attributed to the auto-compensation between C related donors and acceptors, as assumed here. Finally, a similar C-doping model with high donor-acceptor auto-compensation was found also by other authors to be instrumental to reproduce breakdown effects in C-doped AlGaN/GaN HEMTs by means of device simulations [15].…”

Reduction of on-resistance and current crowding in quasi-vertical GaN power diodes

“…19,20 In wafer II, the low N D $ 1 Â 10 16 cm À3 was achieved by lightly carbon doping 21 to compensate the non-intentional-doping. 3, 21 Wafer IV was used as a reference, and it was not optimized to lower the N D in n À -GaN and increase N D in n þ -GaN. This wafer was also used to calibrate our simulation model for a large range of variations in device structures.…”