共查询到19条相似文献,搜索用时 156 毫秒
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本文计算了调制掺杂Ga_(1-x)Al_xA_3-GaAs异质结2DEG场效应晶体管(HEMT)电离中心散射电子迁移率μ_1.给出了μ_1与掺杂Ga_(1-x)Al_xA_s层的厚度d,掺杂浓度N_D,非掺杂的ca_(1-x)Al_xA_s层的厚度δ以及二维电子气的电荷面密度N_s的关系. 相似文献
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用射频等离子体辅助分子束外延技术 (RF- MBE)在 C面蓝宝石衬底上外延了高质量的 Ga N膜以及 Al Ga N/Ga N极化感应二维电子气材料 .所外延的 Ga N膜室温背景电子浓度为 2× 10 1 7cm- 3 ,相应的电子迁移率为 177cm2 /(V· s) ;Ga N (0 0 0 2 ) X射线衍射摇摆曲线半高宽 (FWHM)为 6′;Al Ga N/Ga N极化感应二维电子气材料的室温电子迁移率为 730 cm2 /(V· s) ,相应的电子气面密度为 7.6× 10 1 2 cm- 2 ;用此二维电子气材料制作的异质结场效应晶体管 (HFET)室温跨导达 5 0 m S/mm (栅长 1μm) ,截止频率达 13GHz(栅长 0 .5 μm) 相似文献
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用射频等离子体辅助分子束外延技术(RF-MBE)在C面蓝宝石衬底上外延了高质量的GaN膜以及AlGaN/GaN极化感应二维电子气材料.所外延的GaN膜室温背景电子浓度为2×1017cm-a,相应的电子迁移率为177cm2/(V·s);GaN(0002)X射线衍射摇摆曲线半高宽(FWHM)为6′;AlGaN/GaN极化感应二维电子气材料的室温电子迁移率为730cm2/(V·s),相应的电子气面密度为7.6×1012cm-2;用此二维电子气材料制作的异质结场效应晶体管(HFET)室温跨导达50mS/mm(栅长1μm),截止频率达13GHz(栅长0.5μm). 相似文献
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用射频等离子体辅助分子束外延技术( RF- MBE)在c面蓝宝石衬底上外延了高质量的Ga N膜以及Al N/Ga N超晶格结构极化感应二维电子气材料.所获得的掺Si的Ga N膜室温电子浓度为2 .2e1 8cm- 3,相应的电子迁移率为2 2 1cm2 /( V·s) ;1μm厚的Ga N外延膜的( 0 0 0 2 ) X射线衍射摇摆曲线半高宽( FWHM)为7′;极化感应产生的二维电子气室温电子迁移率达到10 86cm2 /( V·s) ,相应的二维电子气面密度为7.5e1 2 cm- 2 . 相似文献
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在一定的边界条件近似下,通过联立求解泊松和薛定谔方程,利用电荷控制模型对赝型高电子迁移率器件(p-HEMT)进行了模拟,分析了器件中二维电子气的面密度n、6面掺杂层距离表面层厚度d1和距离二维电子气厚度d2对器件特性的影响,并讨论了这些结构参数的优化,为制备高温、稳定和有应用前景的单电子晶体管器件提供了依据. 相似文献
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用自组装的氨源分子束外延 (NH3-MBE)系统和射频等离子体辅助分子束外延 (PA-MBE)系统在 C面蓝宝石衬底上外延了优质 Ga N以及 Al Ga N/Ga N二维电子气材料。Ga N膜 (1 .2 μm厚 )室温电子迁移率达3 0 0 cm2 /V· s,背景电子浓度低至 2× 1 0 1 7cm- 3。双晶 X射线衍射 (0 0 0 2 )摇摆曲线半高宽为 6arcmin。 Al Ga N/Ga N二维电子气材料最高的室温和 77K二维电子气电子迁移率分别为 73 0 cm2 /V·s和 1 2 0 0 cm2 /V· s,相应的电子面密度分别是 7.6× 1 0 1 2 cm- 2和 7.1× 1 0 1 2 cm- 2 ;用所外延的 Al Ga N/Ga N二维电子气材料制备出了性能良好的 Al Ga N/Ga N HFET(异质结场效应晶体管 ) ,室温跨导为 5 0 m S/mm(栅长 1 μm) ,截止频率达 1 3 GHz(栅长 0 .5μm)。该器件在 3 0 0°C出现明显的并联电导 ,这可能是材料中的深中心在高温被激活所致 相似文献
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用射频等离子体辅助分子束外延技术(RF-MBE)在c面蓝宝石衬底上外延了高质量的GaN膜以及AlN/GaN超晶格结构极化感应二维电子气材料.所获得的掺Si的GaN膜室温电子浓度为2.2×1018cm-3,相应的电子迁移率为221cm2/(V*s);1μm厚的GaN外延膜的(0002)X射线衍射摇摆曲线半高宽(FWHM)为7′;极化感应产生的二维电子气室温电子迁移率达到1086cm2/(V*s),相应的二维电子气面密度为7.5×1012cm-2. 相似文献
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We report on temperature dependencies of the electron mobility in the two-dimensional electron gas (2DEG) in AIGaN/GaN heterostructures
and in doped bulk GaN. Calculations and experimental data show that the polar optical scattering and ionized impurity scattering
are the two dominant scattering mechanisms in bulk GaN for temperatures between 77 and 500K. In the 2DEG in AIGaN/GaN heterostructures,
the piezoelectric scattering also plays an important role. Even for doped GaN, with a significant concentration of ionized
impurities, a large volume electron concentration in the 2DEG significantly enhances the electron mobility, and the mobility
values close to 1700 cm2/Vs may be obtained in the GaN 2DEG at room temperature. The maximum measured Hall mobility at 80K is nearly 5000 cm2/Vs compared to approximately 1200 cm2/Vs in a bulk GaN layer. With a change in temperature from 300 to 80K, the 2DEG in our samples changes from nondegenerate
and weakly degenerate to degenerate. Therefore, in order to interpret the experimental data, we propose a new interpolation
formula for low field mobility limited by the ionized impurity scattering. This formula is valid for an arbitrary degree of
the electron gas degeneracy. Based on our theory, we show that the mobility enhancement in the 2DEG is related to a much higher
volume electron concentration in the 2DEG, and, hence, to a more effective screening. 相似文献
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采用高温Hall测量仪对一个全应变和一个部分应变弛豫的AlGaN/GaN异质结构中2DEG的高温输运特性进行了研究,温度变化范围从室温到680K.研究结果表明:在高温段2DEG的迁移率主要受LO声子散射限制; 在室温,异质界面处的非均匀压电极化场对2DEG迁移率的散射也是一个主要的散射机制.同时,计算结果显示,随着温度升高,更多的电子跃迁到更高的子带,在更高的子带,其波函数逐渐扩展到AlGaN层内部以及GaN体内更深的位置,导致LO声子散射的屏蔽效应减弱且来自AlGaN层内的合金无序散射增强. 相似文献
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Y. Q. Tao D. J. Chen Y. C. Kong B. Shen Z. L. Xie P. Han R. Zhang Y. D. Zheng 《Journal of Electronic Materials》2006,35(4):722-725
Transport properties of the two-dimensional electron gas (2DEG) in fully strained and partially strain-relaxed Al0.22Ga0.78N/GaN heterostructures at temperatures from 300 to 680 K have been investigated by Hall effect measurements. The 2DEG mobility
was found to decrease rapidly with increasing temperature at the initial stage and then decrease slowly as temperature is
further increased. Those features indicate strongly that the 2DEG mobility is primarily limited by LO phonon scattering processes
at high temperatures. Meanwhile, the calculated results show that more electrons transfer to the higher-order sub-bands with
increasing temperature, and hence the effect of screening on LO phonon scattering is weakened and the alloy scattering of
the AlGaN layer on the 2DEG becomes stronger. Thus variation of 2DEG occupation in different sub-bands with increasing temperature
also decreases mobility of the 2DEG. 相似文献
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G.A. Umana-Membreno T.B. FehlbergS. Kolluri D.F. BrownG. Parish B.D. NenerS. Keller U.K. MishraL. Faraone 《Microelectronic Engineering》2011,88(7):1079-1082
In this work, we present results of a study of anisotropic two-dimensional electron gas (2DEG) transport in N-polar GaN/AlGaN heterostructures grown on slightly mis-oriented sapphire substrates. High-resolution mobility spectrum analysis of magnetic-field dependent Hall-effect and resistivity indicate an isotropic 2DEG sheet carrier density, yet significant anisotropy was observed in carrier mobility. A single electron species with a narrow mobility distribution was found to be responsible for conduction parallel to the multi-atomic steps resulting from growth on the vicinal substrates; whilst in the perpendicular direction two distinct electrons peaks are evident at T ? 150 K, which merge near room temperature. The linewidth of the mobility distributions for transport in the perpendicular direction was found to be significantly broader than that of the single electron in the parallel direction. The broader mobility distribution and the lower average mobility for the 2DEG in the perpendicular direction are attributable to interface roughness scattering associated with the GaN/AlGaN interfacial steps. 相似文献
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在GaN NMOSFET中,沟道电子由于受垂直于其运动方向电场的作用而产生界面散射,从而影响MOSFET特性.研究采用Monte Carlo体模拟方法计算钎锌矿相GaN材料在界面散射下的电子输运特性.模拟中在电子漂移方向加一个水平电场,同时在与其垂直的方向加另外一个电场,在垂直电场作用下,电子发生界面散射.采用基于指数... 相似文献
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Based on the measured capacitance–voltage(C–V) curves and current–voltage(I–V) curves for the prepared differently-sized Al N/Ga N heterostructure field-effect transistors(HFETs), the I–V characteristics of the Al N/Ga N HFETs were simulated using the quasi-two-dimensional(quasi-2D) model. By analyzing the variation in the electron mobility for the two-dimensional electron gas(2DEG) with the channel electric field, it is found that the different polarization charge distribution generated by the different channel electric field distribution can result in different polarization Coulomb field(PCF) scattering. The 2DEG electron mobility difference is mostly caused by the PCF scattering which can reach up to 899.6 cm2/(V s)(sample a), 1307.4 cm2/(V s)(sample b),1561.7 cm2/(V s)(sample c) and 678.1 cm2/(V s)(sample d), respectively. When the 2DEG sheet density is modulated by the drain–source bias, the electron mobility for samples a, b and c appear to peak with the variation of the 2DEG sheet density, but for sample d, no peak appears and the electron mobility rises with the increase in the2 DEG sheet density. 相似文献
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Characteristics study of 2DEG transport properties of AlGaN/GaN and AlGaAs/GaAs-based HEMT 总被引:3,自引:0,他引:3
Growth of wide bandgap material over narrow bandgap material, results into a two dimensional electron gas (2DEG) at the heterointerface
due to the conduction band discontinuity. In this paper the 2DEG transport properties of AlGaN/GaN-based high electron mobility
transistor (HEMT) is discussed and its effect on various characteristics such as 2DEG density, C-V characteristics and Sheet resistances for different mole fractions are presented. The obtained results are also compared
with AlGaAs/GaAs-based HEMT for the same structural parameter as like AlGaN/GaN-based HEMT. The calculated results of electron
sheet concentration as a function of the Al mole fraction are in excellent agreement with some experimental data available
in the literature. 相似文献
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Transport-Coefficient Dependence of Current-Induced Cooling Effect in a Two-Dimensional Electron Gas
Naomi Hirayama Akira Endo Kazuhiro Fujita Yasuhiro Hasegawa Naomichi Hatano Hiroaki Nakamura Ryōen Shirasaki Kenji Yonemitsu 《Journal of Electronic Materials》2012,41(6):1535-1539
The dependence of the current-induced cooling effect on the electron mobility??? e is explored for a two-dimensional electron gas (2DEG) subjected to a perpendicular magnetic field. We calculate the distributions of the electrochemical potentials and the temperatures under a magnetic field, fully taking account of thermoelectric and thermomagnetic phenomena. Whereas the electrochemical potential and the electric current remain qualitatively unchanged, the temperature distribution exhibits drastic mobility dependence. The lower-mobility system has cold and hot areas at opposite corners, which results from the heat current brought about by the Ettingshausen effect in the vicinity of the adiabatic boundaries. The cooling effect is intensified by an increase in??? e. Intriguingly, the cold and hot areas change places with each other as the mobility??? e is further increased. This is because the heating current on the adiabatic edges due to the Righi?CLeduc effect exceeds that due to the Ettingshausen effect in the opposite direction. 相似文献