In this paper, in order to solve the interface-trap issue and enhance the transconductance induced by high-k dielectric in metal-insulator-semiconductor （MIS） high electron mobility transistors （HEMTs）, we demonst...In this paper, in order to solve the interface-trap issue and enhance the transconductance induced by high-k dielectric in metal-insulator-semiconductor （MIS） high electron mobility transistors （HEMTs）, we demonstrate better performances of recessed-gate A1203 MIS-HEMTs which are fabricated by Fluorine-based Si3N4 etching and chlorine- based A1CaN etching with three etching times （15 s, 17 s and 19 s）. The gate leakage current of MIS-HEMT is about three orders of magnitude lower than that of A1GaN/CaN HEMT. Through the recessed-gate etching, the transconductanee increases effectively. When the recessed-gate depth is 1.02 nm, the best interface performance with Tit----（0.20--1.59） p^s and Dit ：（0.55-1.08）x 1012 cm-2.eV- 1 can be obtained. After chlorine-based etching, the interface trap density reduces considerably without generating any new type of trap. The accumulated chlorine ions and the N vacancies in the AIGaN surface caused by the plasma etching can degrade the breakdown and the high frequency performances of devices. By comparing the characteristics of recessed-gate MIS-HEMTs with different etching times, it is found that a low power chlorine-based plasma etching for a short time （15 s in this paper） can enhance the performances of MIS-HEMTs effectively.展开更多
In this paper,thermoelastic damping （TED） in a micro-beam resonator with a pair of piezoelectric layers bonded on its upper and lower surfaces is investigated.Equation of motion is derived and the thermoelasticity e...In this paper,thermoelastic damping （TED） in a micro-beam resonator with a pair of piezoelectric layers bonded on its upper and lower surfaces is investigated.Equation of motion is derived and the thermoelasticity equation is governed using two dimensional non-Fourier heat conduction model based on continuum theory frame.Applying Galerkin discretization method and complex-frequency approach to solve the equations of coupled thermoelasticity,we study TED of a clamped-clamped micro-beam resonator.The presented results demonstrate that thickness of the piezoelectric layers and application of DC voltage to them can affect the TED ratio and the critical thickness value of the resonator.展开更多
基金supported by the National Key Science and Technology Special Project,China (Grant No. 2008ZX01002-002)the National Natural Science Foundation of China (Grant No. 60736033)
文摘In this paper, in order to solve the interface-trap issue and enhance the transconductance induced by high-k dielectric in metal-insulator-semiconductor （MIS） high electron mobility transistors （HEMTs）, we demonstrate better performances of recessed-gate A1203 MIS-HEMTs which are fabricated by Fluorine-based Si3N4 etching and chlorine- based A1CaN etching with three etching times （15 s, 17 s and 19 s）. The gate leakage current of MIS-HEMT is about three orders of magnitude lower than that of A1GaN/CaN HEMT. Through the recessed-gate etching, the transconductanee increases effectively. When the recessed-gate depth is 1.02 nm, the best interface performance with Tit----（0.20--1.59） p^s and Dit ：（0.55-1.08）x 1012 cm-2.eV- 1 can be obtained. After chlorine-based etching, the interface trap density reduces considerably without generating any new type of trap. The accumulated chlorine ions and the N vacancies in the AIGaN surface caused by the plasma etching can degrade the breakdown and the high frequency performances of devices. By comparing the characteristics of recessed-gate MIS-HEMTs with different etching times, it is found that a low power chlorine-based plasma etching for a short time （15 s in this paper） can enhance the performances of MIS-HEMTs effectively.
文摘In this paper,thermoelastic damping （TED） in a micro-beam resonator with a pair of piezoelectric layers bonded on its upper and lower surfaces is investigated.Equation of motion is derived and the thermoelasticity equation is governed using two dimensional non-Fourier heat conduction model based on continuum theory frame.Applying Galerkin discretization method and complex-frequency approach to solve the equations of coupled thermoelasticity,we study TED of a clamped-clamped micro-beam resonator.The presented results demonstrate that thickness of the piezoelectric layers and application of DC voltage to them can affect the TED ratio and the critical thickness value of the resonator.
