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61.
We studied silver barrier ohmic (Ni/AuGe/Ag/Au) contacts to the GaAs based HEMT structures and observed strong dependence
of the cleaning procedures on the ohmic con-tact resistance (Rc), its stability and reliability. The chemical profiles of the metal con-tacts before and after alloying were measured by
SIMS. Samples cleaned with the com-bined plasma O2 and NH4OH process exhibited excellent results:R
c ∼ 0.1–0.12 ohm-mm when alloyed in the temperature range of 440–540° C and remained stable when subjected to a 200° C and
600mA/mm stress condition for 1000 hr. 相似文献
62.
Andreas Richter Ken-ichi Matsuda Tatsushi Akazaki Tadashi Saku Hiroyuki Tamura Yoshiro Hirayama Hideaki Takayanagi 《Physica E: Low-dimensional Systems and Nanostructures》2005,25(4):472-478
We present studies on the electric transport in a lateral GaAs/AlGaAs quantum dot defined by a patterned single connected metallic front-gate. This gate design allows to easily couple a large number of quantum dots and therefore holds high potential in the design of new materials with tailor-made band structures based on quantum dot superlattices of controlled shape. Clear Coulomb diamond structures and well pronounced tunneling peaks observed in experiment indicate that single-electron control has been achieved. However, the dependence on electron density in the heterostructure embedding the dot, which is controlled by an additional back-gate, reveals that transport characteristics are strongly influenced supposedly by potential fluctuations in the dot and lead regions. 相似文献
63.
Zhang Haiying Liu Xunchun Yin Junjian Chen Liqiang Wang Runmei Niu Jiebin and Liu Ming 《半导体学报》2005,26(6):1126-1128
Millimeterwave transistor technology is very important for MMIC design and fabrication.An InP HEMT with sawtoothed source and drain is described.The pattern distortion due to the proximity effect of lithography is avoided.High yield InP HEMT with good DC and RF performances is obtained.The device transconductance is 1050mS/mm,threshold voltage is -1.0V,and current gain cut off frequency is 120GHz. 相似文献
64.
65.
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
66.
A. Fontserè A. Pérez-TomásM. Placidi P. Fernández-MartínezN. Baron S. ChenotY. Cordier J.C. MorenoP.M. Gammon M.R. Jennings 《Microelectronic Engineering》2011,88(10):3140-3144
In this paper two types of Al/Ti-based Ohmic contacts to Gallium Nitride (GaN) based devices are presented; ImplantedN+GaN (like the ones found in the Source/Drain of GaN Metal Oxide Semiconductor Field Effect Transistors-MOSFET) and heterojunction (HJ) AlGaN/GaN contacts (Source/Drain of High Electron Mobility Transistors-HEMT). Sheet resistance (Rsh) and contact resistance (Rc) have been investigated in the temperature (T) range of 25-250 °C. It was found that the Rsh (850/700 Ω□) (25/250 °C) and Rc (2.2/0.7 Ωmm) decrease with T for ImplantedN+GaN contact and Rsh (400/850 Ω□) and Rc (0.2/0.4 Ωmm) (weakly for Rc) increase with T for HJAlGaN/GaN contact. Numerical computation based models are used to determine the theoretical Rsh and Rc behavior with T and to fit the experimental values. 相似文献
67.
本文报道了fmax为200GHz的基于蓝宝石衬底的AlGaN/GaN 高电子迁移率晶体管(HEMT)。外延材料结构采用了InGaN背势垒层来减小短沟道效应,器件采用了凹栅槽和T型栅结合的工艺,实现了Ka波段AlGaN/GaN HEMT。器件饱和电流达到1.1A/mm,跨导为421mS/mm,截止频率(fT)为30GHz,最大振荡频率(fmax)为105GHz。采用了湿法腐蚀工艺将器件的Si3N4钝化层去除后,器件的Cgs和Cgd减小,器件截止频率提高到50GHz,最大振荡频率提高到200GHz。 相似文献
68.
H. Sasaki DG K. Yajima N. Yoshida T. Ishida R. Hattori T. Sonoda O. Ishihara S. Takamiya R. Konishi K. Ando 《Journal of Electronic Materials》1996,25(5):559-563
We have investigated the degradation mechanism of Al0.48In0.52As/In0.53Ga0.47As/ InP high electron mobility transistors (HEMTs) using WSi ohmic electrodes. Cross-sectional transmission electron microscopy
(TEM) observation and en-ergy dispersive x-ray (EDX) analysis reveal impurities diffusion of gate electrode (titanium: Ti)
and fluorine (F) in the AlInAs layer after a high temperature (Ta = 170°C operating life test for 500 h. The decrease of drain current (Ids) during life test shows linear dependence on square root of aging time. It suggests that the degradation is controlled by
a diffusion mechanism. Hence, the estimated degradation mechanism of this device is related with decrease of carrier concentration
in the epitaxial layer by these diffused impurities. On the other hand, TEM and EDX show no degradation of WSi/InGaAs interface
after aging. Therefore, the WSi electrode for this type of HEMT demonstrates excellent high stability under the accelerated
operating life test. 相似文献
69.
本文选择了适于单片微波集成的移相器设计方案,使用砷化钾(GaAs)0.5μm高电子迁移率晶体管(HEMT)工艺原型,经微波电路、电场仿真,设计出五位移相器,并试制了180°位样片。试制样品尺寸1.5×1.0mm2,测试结果性能良好,在2.5~5.0GHz带宽内,移相起伏小于10;°在2.6~3.5GHz带宽内,移相起伏小于5°,同设计仿真结果基本吻合。 相似文献
70.