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Simulation of the influence of interface states on capacitance characteristics of insulator/ A l G a N / G a N heterojunctions
Author(s) -
Osvald J.
Publication year - 2013
Publication title -
physica status solidi (a)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.532
H-Index - 104
eISSN - 1862-6319
pISSN - 1862-6300
DOI - 10.1002/pssa.201228644
Subject(s) - heterojunction , capacitance , materials science , semiconductor , condensed matter physics , optoelectronics , insulator (electricity) , acceptor , oxide , chemistry , electrode , physics , metallurgy
We have studied numerically the capacitance properties of insulator/AlGaN/GaN MIS heterostructures and the influence of interface traps on the capacitance curves shape. By using the basic semiconductor equations we simulated the capacitance–voltage ( C – V ) curves of these structures for high‐frequency signals. We obtained two steps in the C – V curves. The curves with the interface traps are shifted in voltage at both steps depending on whether the trap is of an acceptor or a donor type. The new knowledge found is that the shift caused by the change of the population of interface states is overlapped in almost the whole semiconductor energy gap by a charge change in a two‐dimensional electron gas (2DEG). Finally, the presence of deep levels causes widening of the capacitance plateau instead of stretching of the C – V curves. So, the assessment of interface states density for MIS heterostructures is not expected to be so straightforward like in Si metal oxide semiconductor structures.