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21.
Theoretical investigation of incomplete ionization of dopants in uniform and ion-implanted 4H-SiC MESFETs
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The effects of incomplete ionization of nitrogen in 4H-SiC have
been investigated. Poisson's equation is numerically analysed by
considering the effects of Poole--Frenkel, and the effects of
the potential on $N^+_\dd$ (the concentration of ionized donors)
and $n$ (the concentration of electrons). The pinch-off voltages
of the uniform and the ion-implanted channels of 4H-SiC
metal-semiconductor field-effect transistors (MESFETs) and
the capacitance of the gate are given at different temperatures.
Both the Poole--Frenkel effect and the potential have influence on
the pinch-off voltage $V_{\rm p}$ of 4H-SiC MESFETs. Although the
$C$-$V$ characteristics of the ion-implanted and the uniform channel of
4H-SiC MESFETs have a clear distinction, the effects of incomplete
ionization on the $C$-$V$ characteristics are not significant. 相似文献
22.
Numerical simulation of transconductance of AlGaN/GaN heterojunction field effect transistors at high temperatures
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Based on the investigation of the influence of temperatures on
parameters, including polarization, electron mobility, thermal conductivity,
and conduction band discontinuity at the interface between AlGaN and GaN,
the temperature dependence of transconductance for AlGaN/GaN heterojunction
field effect transistors (HFETs) has been obtained by using a
quasi-two-dimensional approach, and the calculated results are in good
agreement with the
experimental data. The reduction in transconductance at high
temperatures is
primarily due to the decrease in electron mobility in the channel.
Calculations also demonstrate that the self-heating effect becomes serious
as environment temperature increases. 相似文献
23.
Formation of the intermediate semiconductor larger for the Ohmic contact to silicon carbide using Germanium implantation
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By formation of an intermediate semiconductor layer (ISL) with a
narrow band gap at the metallic contact/SiC interface, this paper
realises a new method to fabricate the low-resistance Ohmic contacts
for SiC. An array of transfer length method (TLM) test patterns is
formed on N-wells created by P+ ion implantation into
Si-faced p-type 4H-SiC epilayer. The ISL of nickel-metal Ohmic
contacts to n-type 4H-SiC could be formed by using Germanium ion
implantation into SiC. The specific contact resistance ρc as low as 4.23× 10-5~Ωega \cdotcm2 is
achieved after annealing in N2 at 800~°C for 3~min,
which is much lower than that (>900~°C) in the typical SiC
metallisation process. The sheet resistance Rsh of the
implanted layers is 1.5~kΩega /\Box. The technique for
converting photoresist into nanocrystalline graphite is used to
protect the SiC surface in the annealing after Ge+ ion
implantations. 相似文献
24.
将随机游走法和等效电路压缩相结合,对静态P/G网(Power and Ground Networks)进行分析.针对一个大规模的电路,在经过多层的参数提取和建模后,得到静态P/G网模型.首先根据网络的规律性,运用等效电路压缩法将原始的P/G网进行压缩处理,然后运用随机游走法求解,最后利用计算得到的化简网络电压值,通过相关的插值公式得到原网络的电压值.实验数据表明,改进的压缩式随机游走法可有效简化网络的复杂性,节省计算时间,计算速度提高到普通随机游走法的两个数量级以上. 相似文献
25.
The diffusion behaviours of vanadium implanted p- and
n-type 4H-SiC are investigated by using the secondary
ion mass spectrometry (SIMS).
Significant redistribution, especially out-diffusion of vanadium towards the
sample surface is not observed after 1650℃ annealing for both p-
and n-type samples. Atomic force microscopy (AFM) is applied to the
characterization of
surface morphology, indicating the formation of continuous long furrows
running in one direction across the wafer surface after 1650℃
annealing. The surface roughness results from the
evaporation and re-deposition of
Si species on the surface during annealing. The chemical compositions of
sample surface are investigated using x-ray photoelectron spectroscopy (XPS).
The results of C 1s and Si 2p core-level spectra are presented in detail to
demonstrate the evaporation of Si from the wafer and the deposition of SiO2
on the sample surface during annealing. 相似文献
26.
27.
提出了一种SiC反型层表面粗糙散射的指数模型,并对6H-SiC反型层迁移率进行了单电子的Monte Carlo模拟,模拟中考虑了沟道区的量子化效应.模拟结果表明,采用表面粗糙散射的指数模型能够使SiC反型层迁移率的模拟结果和实验值符合得更好.模拟结果还反映出有效横向电场较高时表面粗糙散射的作用会变得更显著,电子的屏蔽效应降低了粗糙散射对沟道迁移率的影响,温度升高会引起沟道迁移率降低.
关键词:
6H-SiC
反型层迁移率
表面粗糙散射
指数模型 相似文献
28.
29.
30.
The consecutive reaction of bis [ 2, 2, 2-trifluoroethyl] phosphite and its application to the one-pot synthesis of 3-cyano-β, γ-unsaturated nitriles with exdusive or predominant E-selectivity (E: Z = 100-85: 0-15) and excellent yields (94%-99%) are described. 相似文献