The physical mechanisms of Ti/Al/Ni/Au ohmic contacts to AlGaN/GaN heterostructures by laser annealing and rapid thermal annealing are systematically investigated. The microstructures indicate that a better surface mo...The physical mechanisms of Ti/Al/Ni/Au ohmic contacts to AlGaN/GaN heterostructures by laser annealing and rapid thermal annealing are systematically investigated. The microstructures indicate that a better surface morphology and an intact contact interface are formed after laser annealing. None of the TiN alloy spikes are formed at the interface of the laser annealing sample. The experimental results show that the current transport mechanism through the ohmic contact after laser annealing is different from the conventional spike mechanism, and it is dominated by thermionic field emission.展开更多
AlGaN/GaN high-electron-mobility transistors with Au-free ohmic contacts are fabricated by selective laser annealing and conventional rapid thermal annealing.The current transport mechanism of ohmic contacts is invest...AlGaN/GaN high-electron-mobility transistors with Au-free ohmic contacts are fabricated by selective laser annealing and conventional rapid thermal annealing.The current transport mechanism of ohmic contacts is investigated.High-temperature annealing can be avoided in the isolated region and the active region by selective laser annealing.The implanted isolation leakage current is maintained 10^(-6) mA/mm even at 1000 V after selective laser annealing.On the contrary,high-temperature annealing will cause obvious degradation of the isolation.The morphology of AlGaN surface is measured by atomic force microscope.No noticeable change of the AlGaN surface morphology after selective laser annealing,while the root-mean-square roughness value markedly increases after rapid thermal annealing.The smaller frequency dispersion of capacitance-voltage characteristics confirms the lower density of surface states after selective laser annealing.Thus,dynamic on-resistance is effectively suppressed.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.51577169 and 51777187)the National Key Research and Development Program of China(Grant No.2017YFB0402804)
文摘The physical mechanisms of Ti/Al/Ni/Au ohmic contacts to AlGaN/GaN heterostructures by laser annealing and rapid thermal annealing are systematically investigated. The microstructures indicate that a better surface morphology and an intact contact interface are formed after laser annealing. None of the TiN alloy spikes are formed at the interface of the laser annealing sample. The experimental results show that the current transport mechanism through the ohmic contact after laser annealing is different from the conventional spike mechanism, and it is dominated by thermionic field emission.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.51577169 and 51777187)the National Key Research and Development Program of China(Grant No.2017YFB0402804)the“Science and Technology Innovation 2025”Major Program of Ningbo(Grant No.2018B10098).
文摘AlGaN/GaN high-electron-mobility transistors with Au-free ohmic contacts are fabricated by selective laser annealing and conventional rapid thermal annealing.The current transport mechanism of ohmic contacts is investigated.High-temperature annealing can be avoided in the isolated region and the active region by selective laser annealing.The implanted isolation leakage current is maintained 10^(-6) mA/mm even at 1000 V after selective laser annealing.On the contrary,high-temperature annealing will cause obvious degradation of the isolation.The morphology of AlGaN surface is measured by atomic force microscope.No noticeable change of the AlGaN surface morphology after selective laser annealing,while the root-mean-square roughness value markedly increases after rapid thermal annealing.The smaller frequency dispersion of capacitance-voltage characteristics confirms the lower density of surface states after selective laser annealing.Thus,dynamic on-resistance is effectively suppressed.
