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121.
初步分析了AlGaN/GaN 器件上的kink效应. 在直流模型的基础上, 建立了AlGaN/GaN 高电子迁移率晶体管中kink效应的半经验模型, 并加入了kink效应发生的漏源偏压与栅源偏压的关系. 该模型得出较为准确的模拟结果, 可用来判断kink效应的发生和电流的变化量. 最后, 我们采用模型仿真结合实验分析的方法, 对kink效应进行了一定的物理研究, 结果表明碰撞电离对kink效应的发生有一定的促进作用. 相似文献
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AlGaN/GaN high electron mobility transistors (HEMTs) were exposed to 1 MeV neutron irradiation at a neutron fluence of 1 × 1015 cm-2. The dc characteristics of the devices, such as the drain saturation current and the maximum transconductance, decreased after neutron irradiation. The gate leakage currents increased obviously after neutron irradiation. However, the rf characteristics, such as the cut-off frequency and the maximum frequency, were hardly affected by neutron irradiation. The AlGaN/GaN heterojunctions have been employed for the better understanding of the degradation mechanism. It is shown in the Hall measurements and capacitance-voltage tests that the mobility and concentration of two-dimensional electron gas (2DEG) decreased after neutron irradiation. There was no evidence of the full-width at half-maximum of X-ray diffraction (XRD) rocking curve changing after irradiation, so the dislocation was not influenced by neutron irradiation. It is concluded that the point defects induced in AlGaN and GaN by neutron irradiation are the dominant mechanisms responsible for performance degradations of AlGaN/GaN HEMT devices. 相似文献
124.
We study the dynamic behavior of marginal metallic glass-forming liquids Al-Ni-M (M=La, Pr, Nd) in terms of liquid fragility in high and low temperature regions. The liquids are extremely fragile above the liquidus temperature T liq, but become rather strong near the glass transition temperature Tg. The strength of the transition is inversely correlated with the fragility index at Tg. This relation is discussed in terms of potential energy landscape. 相似文献
125.
Fabrication and Characteristics of AIInN/A1N/GaN MOS-HEMTs with Ultra-Thin Atomic Layer Deposited Al2O3 Gate Dielectric
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Al0.85In0.15N//AlN/GaN metal-oxide-semiconductor high electron mobility transistors (MOS-HEMTs) employing a 3-nm ultra-thin atomic-layer deposited (ALD) Al2O3 gate dielectric layer are reported. Devices with 0.6μm gate lengths exhibit an improved maximum drain current density of 1227mA/mm at a gate bias of 3 V, a peak transeonductance of 328mS/mm, a cutoff frequency fr of 16 GHz, a maximum frequency of oscillation fmax of 45 GHz, as well as significant gate leakage suppression in both reverse and forward directions, compared with the conventionM Al0.85In0.15N/AlN/GaN HEMT. Negligible C - V hysteresis, together with a smaller pinch-off voltage shift, is observed, demonstrating few bulk traps in the dielectric and high quality of the Al2O3/AIInN interface, it is most notable that not only the transconductance profile of the MOS-HEMT is almost the same as that of the conventional HEMT with a negative shift, but also the peak transconduetance of the MOS-HEMT is increased slightly. It is an exeitin~ inwrovement in the transconductance performance. 相似文献
126.
Morphology of nonpolar (1120) a-plane GaN epilayers on r-plane (1102) sapphire substrate grown by low-pressure metal-organic vapour deposition was investigated after KOH solution etching. Many micron-and nano-meter columns on the a-plane GaN surface were observed by scanning electron microscopy. An etching mechanism model is proposed to interpret the origin of the peculiar etching morphology. The basal stacking fault in the a-plane GaN plays a very important role in the etching process. 相似文献
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采用O2等离子体及HF溶液对AlGaN/GaN异质结材料进行表面处理后,Ni/Au肖特基接触特性比未处理有了明显改善,反向泄漏电流减小3个数量级.对制备的肖特基接触进行200—600℃ 5min的N2气氛退火,发现退火冷却后肖特基反向泄漏电流随退火温度增大进一步减小.N2气中600℃退火后肖特基二极管C-V特性曲线在不同频率下一致性变好,这表明退火中Ni向材料表面扩散减小了表面陷阱密度;C-V特性曲线随退火温度增大向右移动,从二维电子气耗尽电压绝对值减小反映了肖特基势垒的提高.
关键词:
AlGaN/GaN
肖特基接触
表面处理
退火 相似文献
129.
基于完全对角化方法,研究了4B1(3d3)态离子在四角对称晶场中的磁相互作用,分析了自旋哈密顿参量(b02, g∥, g⊥, Δg)的微观起源.结果表明:在被考虑的大部分晶场区域,人们通常考虑的SO(spin-orbit)磁相互作用的贡献最为重要;然而,对于零场分裂参量b02而言,来自其他机理(包括SS(spin-orbit),SOO(spin-other-orbit),SO-SS-SOO)的贡献在大部分晶场区域超过了20%;在部分晶场区域,其他机理的贡献甚至超过SO机理的贡献.详细地分析了Macfarlane 零场分裂参量b02近似三阶微扰理论的收敛性,结果表明:该理论在大部分晶场区域收敛性较差.讨论了3d3态离子第一激发态2Eg分裂的微观起源.并利用群论方法解释了在C4v和C3v对称晶场中2Eg态分裂的不同机理. 相似文献
130.
Degradation mechanism of enhancement-mode AlGaN/GaN HEMTs using fluorine ion implantation under the on-state gate overdrive stress
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The degradation mechanism of enhancement-mode Al Ga N/Ga N high electron mobility transistors(HEMTs)fabricated by fluorine plasma ion implantation technology is one major concern of HEMT’s reliability.It is observed that the threshold voltage shows a significant negative shift during the typical long-term on-state gate overdrive stress.The degradation does not originate from the presence of as-grown traps in the Al Ga N barrier layer or the generated traps during fluorine ion implantation process.By comparing the relationships between the shift of threshold voltage and the cumulative injected electrons under different stress conditions,a good agreement is observed.It provides direct experimental evidence to support the impact ionization physical model,in which the degradation of E-mode HEMTs under gate overdrive stress can be explained by the ionization of fluorine ions in the Al Ga N barrier layer by electrons injected from 2DEG channel.Furthermore,our results show that there are few new traps generated in the Al Ga N barrier layer during the gate overdrive stress,and the ionized fluorine ions cannot recapture the electrons. 相似文献