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51.
Systematic designs to achieve normally-off operation and improved device performance for Al0.26Ga0.74N/AlN/GaN high electron mobility transistors (HEMTs) grown on a Si substrate are investigated in this work. The step-by-step approach includes: (1) devising a thin AlGaN/AlN composite barrier, (2) introducing fluoride ions within the active region by using CF4 plasma treatment, (3) growing the Al2O3 oxide passivation layers within gate-drain/source regions by using a cost-effective ozone water oxidization technique, and (4) integrating a metal-oxide-semiconductor gate (MOS-gate) design with high-k Al2O3 gate dielectric. Devices with four different evolutionary gate structures have been compared and studied. Variations of threshold voltage (Vth), Hooge coefficients (αH), maximum drain-source current density (IDS, max), maximum extrinsic transconductance (gm, max), gate-voltage swing (GVS) linearity, two-terminal gate-drain breakdown/turn-on voltages (BVGD/Von), on/off current ratio (Ion/Ioff), and high-temperature characteristics up to 450 K are also investigated. 相似文献
52.
An AlGaN/GaN recessed-gate MOSHEMT was fabricated on a sapphire substrate. The device, which has a gate length of 1 μm and a source-drain distance of 4 μm, exhibits a maximum drain current density of 684 mA/mm at Vgs = 4 V with an extrinsic transconductance of 219 mS/mm. This is 24.3% higher than the transconductance of conventional AlGaN/GaN HEMTs. The cut-off frequency and the maximum frequency of oscillation are 9.2 GHz and 14.1 GHz, respectively. Furthermore, the gate leakage current is two orders of magnitude lower than for the conventional Schottky contact device. 相似文献
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M. Gassoumi M.M. Ben SalemS. Saadaoui B. GrimbertJ. Fontaine C. gaquiereH. Maaref 《Microelectronic Engineering》2011,88(4):370-372
In AlGaN/GaN heterostructure field-effect transistors, the surface defects and dislocations may serve as trapping centers and affect the device performance via leakage current. In this paper we report results of our investigation of the trapping characteristics of Al0.25Ga0.75N/GaN HEMT using the Conductance Deep Level Transient Spectroscopy (CDLTS). Two deep level electronic defects were observed labeled E1 and HL1, with activation energies Ea1 = 1.36 eV and Ea2 = 0.63 eV. The hole-trap HL1 is characterized for the first time in our studies. We identified the characteristics of the traps at the AlGaN/GaN interface adjoining the channel and the surface along the ungated region between the gate and the drain, as well as the effects of the surface traps. 相似文献
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首次采用CF4等离子体技术实现可用于功率变换的增强性AlGaN/GaN功率器件。实验结果表明,当AlGaN/GaN器件经功率150W和时间150s等离子体轰击后,器件阈值电压从-4V被调制约为0.5V,表现为增强型。当漂移区LGD从5μm增加到15μm,器件的击穿电压从50V迅速增大到400V,电压增幅达350V。采用长度为3μm源场板结构将器件击穿电压明显地提高,击穿电压增加约为475V,且有着比硅基器件更低的比导通电阻,约为2.9mΩ.cm2。器件模拟结果表明,因源场板在远离栅边缘的漂移区中引入另一个电场强度为1.5MV/cm的电场,从而有效地释放了存在栅边缘的电场,将高达3MV/cm的电场减小至1MV/cm。微波测试结果表明,器件的特征频率fT和最大震荡频率fMAX随Vgs改变,正常工作时两参数均在千兆量级。栅宽为1mm的增强型功率管有较好的交直流和瞬态特性,正向电流约为90mA。故增强型AlGaN/GaN器件适合高压高频大功率变换的应用。 相似文献
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《Microelectronics Reliability》2014,54(11):2406-2409
Off-state breakdown characteristics of AlGaN/GaN high-electron-mobility transistors have been studied based on drain current injection method. It is found that at low drain current injection level, the observed premature breakdown is caused by excess gate-to-drain leakage current. Nevertheless, at high drain injection current level, buffer-leakage-dominated breakdown proceeds gate-leakage-dominated breakdown as the gate bias increases from pinch-off voltage to deep-depletion voltage. In both breakdown regions, the breakdown voltages show negative temperature coefficients. The buffer-leakage-induced breakdown should be defect-related, which is confirmed by temperature-dependent buffer leakage measurements. 相似文献
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The objective of this work is to simulate a single quantum well ultraviolet light emitting diode (LED) based on AlGaN/GaN/AlGaN and AlGaN/BGaN/AlGaN, by using TCAD Silvaco simulator. The first structure has a GaN quantum well taken between two layers, of n-AlGaN and p-AlGaN. The second one has a BGaN quantum well instead of GaN. We fix the concentration of the boron in BGaN to only 1% and we vary the thickness of GaN and BGaN quantum well layer from 7 to 20 nm, for the two structures. As results, we obtain respectively for GaN-LED and BGaN-LED, a maximum current of 0.52 and 0.27 mA, a maximum power spectral density of 1.935 and 6.7 W cm−1 eV−1, a maximum spontaneous emission of 3.34 × 1028 and 3.43 × 1028 s−1 cm−3 eV−1, and a maximum Light output power of 0.56 and 0.89 mW. 相似文献
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