AlGaN/GaN MISHEMTs with Sodium-Beta-Alumina as the Gate Dielectrics

【摘要】 AlGaN/GaN metal-insulator-semiconductor high-electron-mobility transistors（MISHEMTs） with sodium betaalumina（SBA） thin films as the gate dielectrics are studied.AlGaN/GaN metal-semiconductor high-electronmobility transistors（MESHEMTs） and MISHEMTs with AI₂O₃ thin-film gate dielectrics are also fabricated for comparative study.The MISHEMTs with SBA gate dielectrics show nearly four orders of magnitude lower gate leakage current and an approximately 60%increase in maximum transconductance,indicating that SBA can serve as an effective dielectric for AlGaN/GaN MISHEMTs.However,SBA gate dielectrics result in threshold voltage modulation of AlGaN/GaN MISHEMTs.Compared with those of AlGaN/GaN MESHEMTs,the threshold voltages of AlGaN/GaN MISHEMTs with AI₂O₃ gate dielectrics shift negatively from-5.5 V to-7.5 V.In contrast with the normally used gate dielectrics,the threshold voltages of MISHEMTs with SBA gate dielectrics shift positively from —5.5 V to —3.5 V.Based on an x-ray photoelectron spectrum study and energy band spectrum calculation,the primary mechanism of the threshold voltage modulation is attributed to the decrease in the surface valence-band maximum and the increase in the barrier height by SBA gate dielectrics.更多还原

【Abstract】 AlGaN/GaN metal-insulator-semiconductor high-electron-mobility transistors（MISHEMTs） with sodium betaalumina（SBA） thin films as the gate dielectrics are studied.AlGaN/GaN metal-semiconductor high-electronmobility transistors（MESHEMTs） and MISHEMTs with AI₂O₃ thin-film gate dielectrics are also fabricated for comparative study.The MISHEMTs with SBA gate dielectrics show nearly four orders of magnitude lower gate leakage current and an approximately 60%increase in maximum transconductance,indicating that SBA can serve as an effective dielectric for AlGaN/GaN MISHEMTs.However,SBA gate dielectrics result in threshold voltage modulation of AlGaN/GaN MISHEMTs.Compared with those of AlGaN/GaN MESHEMTs,the threshold voltages of AlGaN/GaN MISHEMTs with AI₂O₃ gate dielectrics shift negatively from-5.5 V to-7.5 V.In contrast with the normally used gate dielectrics,the threshold voltages of MISHEMTs with SBA gate dielectrics shift positively from —5.5 V to —3.5 V.Based on an x-ray photoelectron spectrum study and energy band spectrum calculation,the primary mechanism of the threshold voltage modulation is attributed to the decrease in the surface valence-band maximum and the increase in the barrier height by SBA gate dielectrics.更多还原