We have stressed GaN High Electron Mobility Transistors (HEMTs) with AlGaN back barrier on SiC substrate at high voltages at normal and high temperatures. A pattern of device degradation differs from what occurred in ...
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We have stressed GaN High Electron Mobility Transistors (HEMTs) with AlGaN back barrier on SiC substrate at high voltages at normal and high temperatures. A pattern of device degradation differs from what occurred in reported GaN-on-SiC HEMTs and GaN-on-Si HEMTs. The recoverable degradation of drain current is observed under Vds=0 step stress condition, but no degradation is observed under off-state condition. We attribute the results to electron injection into the back quantum well, other than electron trapping. Raman scattering indicates planar strain is greatly enhanced under Vds=0V condition, which is likely to assist electron in tunneling the back barrier.
The current voltage （IV） characteristics are greatly influenced by the dispersion effects in A1GaN/CaN high electron mobility transistors. The direct current （DC） IV and pulsed IV measurements are performed to giv...
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The current voltage （IV） characteristics are greatly influenced by the dispersion effects in A1GaN/CaN high electron mobility transistors. The direct current （DC） IV and pulsed IV measurements are performed to give a deep investigation into the dispersion effects, which are mainly related to the trap and self-heating mechanisms. The results show that traps play an important role in the kink effects, and high stress can introduce more traps and defects in the device. With the help of the pulsed IV measurements, the trapping effects and self-heating effects can be separated. The impact of time constants on the dispersion effects is also discussed. In order to achieve an accurate static DC IV measurement, the steady state of the bias points must be considered carefully to avoid the dispersion effects.
This paper deduces the expression of the Schottky contact capacitance of AlGaN/A1N/GaN high electron mobility transistors （HEMTs）, which will help to understand the electron depleting process. Some material paramete...
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This paper deduces the expression of the Schottky contact capacitance of AlGaN/A1N/GaN high electron mobility transistors （HEMTs）, which will help to understand the electron depleting process. Some material parameters related with capacitance-voltage profiling are given in the expression. Detailed analysis of the forward-biased capacitance has been carried on. The gate capacitance of undoped AlGaN/AlN/GaN HEMT will fall under forward bias. If a rising profile is obviously observed, the donor-like impurity or trap is possibly introduced in the barrier.
The method of multi-bias capacitance voltage measurement is presented. The physical meaning of gate-source and gate-drain capacitances in AlGaN/GaN HEMT and the variations in them with different bias conditions are di...
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The method of multi-bias capacitance voltage measurement is presented. The physical meaning of gate-source and gate-drain capacitances in AlGaN/GaN HEMT and the variations in them with different bias conditions are discussed. A capacitance model is proposed to reflect the behaviors of the gate-source and gate-drain capacitances, which shows a good agreement with the measured capacitances, and the power performance obtains good results compared with the measured data from the capacitance model.
A high power X-band hybrid microwave integrated voltage controlled oscillator（VCO） based on Al-GaN /GaN HEMT is *** oscillator design utilizes a common-gate negative resistance structure with open and short-circuit ...
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A high power X-band hybrid microwave integrated voltage controlled oscillator（VCO） based on Al-GaN /GaN HEMT is *** oscillator design utilizes a common-gate negative resistance structure with open and short-circuit stub microstrip lines as the main resonator for a high Q *** VCO operating at 20 V drain bias and-1.9 V gate bias exhibits an output power of 28 dBm at the center frequency of 8.15 GHz with an efficiency of 21%.Phase noise is estimated to be -85 dBc/Hz at 100 kHz offset and -128 dBc/Hz at 1 MHz *** tuning range is more than 50 *** dominating effect of GaN HEMT＇s flicker noise on oscillator phase noise performance has also been *** measured results show great promise for AlGaN/GaN HEMT technology to be used in high power and low phase noise microwave source applications.
We carry out a thermal storage research on GaN HEMT at 350℃for 48 h,and a recess phenomenon is observed in the low voltage section of Schottky forward *** decrease of 2DEG density will be responsible for the recess *...
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We carry out a thermal storage research on GaN HEMT at 350℃for 48 h,and a recess phenomenon is observed in the low voltage section of Schottky forward *** decrease of 2DEG density will be responsible for the recess *** the conventional method is not suitable for this kind of curve,a revised approach is presented by analyzing the back-to-back Schottky junction energy band to extract Schottky parameters, which leads to a consistent fit effect.
A novel diffractive optical element, named phase zone photon sieve （PZPS）, is presented. There are three kinds of phase plates in PZPSs： PZPS1, PZPS2, and PZPS3. Each of the PZPSs has its own structure and is made ...
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A novel diffractive optical element, named phase zone photon sieve （PZPS）, is presented. There are three kinds of phase plates in PZPSs： PZPS1, PZPS2, and PZPS3. Each of the PZPSs has its own structure and is made on quartz substrate by etching. The three PZPSs have stronger diffraction peak intensity than a photon sieve （PS） when the margin pinhole and zone line width are kept the same. The PZPS3 can produce a smaller central diffractive spot than the ordinary PS with the same number of zones on the Fresnel zone plate. We have given the design method for and the simulation of PZPS and PS. PZPS has potential applications in optical maskless lithography.
A unified FinFET reliability model including high K stack dynamic threshold (HKSDT), hot carrier injection (HCI), and negative bias temperature instability (NBTI) has been developed and verified by experimental data. ...
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A unified FinFET reliability model including high K stack dynamic threshold (HKSDT), hot carrier injection (HCI), and negative bias temperature instability (NBTI) has been developed and verified by experimental data. The FinFET-based circuit performances are simulated and compared under these reliability issues by HSPICE simulator after the inclusion of the presented model.
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