三材料线性掺杂石墨烯纳米条带场效应管性能(英文)

采用量子动力学模型研究单材料和三材料的石墨烯纳米条带场效应管(GNRFETs)在不同掺杂情况下的弹道输运特性,模型基于非平衡格林函数方程(NEGF)以及自洽的泊松方程的量子数值解.结果证明:三材料线性掺杂的石墨烯纳米条带场效应管(TL-GNRFET)不仅能够有效地抑制短沟道效应(SCE)和漏极势垒降低效应(DIBL),而且相对于其它几种结构而言,它有更好的亚阈值斜率以及更高的开关电流比.另外,还研究了非对称栅结构对石墨烯场效应管的影响,结果表明,当上栅和下栅同时向源端移动的时候,可以改善器件的电流开关比.

漂移区为线性掺杂的高压薄膜SOI器件的研制

给出了漂移区为线性掺杂的高压薄膜SOI器件的设计原理和方法 .在Si膜厚度为 0 15 μm、隐埋氧化层厚度为 2 μm的SOI硅片上进行了LDMOS晶体管的制作 .首次对薄膜SOI功率器件的击穿电压与线性掺杂漂移区的杂质浓度梯度的关系进行了实验研究 .通过对漂移区掺杂剂量的优化 ,所制成的漂移区长度为 5 0 μm的LDMOS晶体管呈现了高达 6 12V的击穿电压 .

具有线性掺杂PN型降场层的新型槽栅LDMOS

文中提出了一种具有线性掺杂PN型降场层的槽栅LDMOS器件(LDPN TG-LDMOS),以期获得较高的击穿电压和较低的导通电阻。线性掺杂PN型降场层能够优化器件的表面电场并降低结处的电场峰值,从而提高器件的击穿电压。同时,线性掺杂PN型降场层对N型漂移区的辅助耗尽作用能够提高器件的漂移区掺杂浓度,从而降低导通电阻。仿真结果表明,与常规的槽栅LDMOS相比,具有线性掺杂PN型降场层的槽栅LDMOS器件的击穿电压提高了28%,导通电阻降低了50%。

渐变层线性掺杂的InGaAs/InP场助阴极的能带结构设计与仿真

为了进一步提高阴极材料的量子效率,设计了一种新的InGaAs/InP转移电子(Transferred Eletron,TE)光电阴极结构,且在不同掺杂浓度、渐变层宽度、外加电压等条件下,利用Matlab仿真工具对能带曲线进行了模拟。实验结果表明:发射层与吸收层的掺杂比例应不高于50;能带曲线得到了更为严格的优化参数范围,可以使表面发射几率进一步提高;且由于计算中考虑掺杂浓度、费米能级移动对能带结构变化的影响,并对描述渐变区能带的双曲函数进行改进,使得计算结果比以往的计算更为准确。结果表明此种结构可以极大地提高阴极的量子效率,对进一步改进阴极参数和制备出更高灵敏度的TE阴极具有实际的指导意义。

改进击穿电压和导通电阻折中性能的线性变化掺杂漂移区RESURF LDMOS晶体管

本文提出了改进击穿电压和导通电阻折中性能的线性变化掺杂漂移区RESURFLDMOS晶体管新结构 .用二维器件软件MEDICI对具有线性变化掺杂漂移区的RESURFLDMOS晶体管的性能进行了数值分析并由实验对其结果进行了验证 .结果表明 :在相同的漂移区长度下 ,该新结构较之于优化的常规RESURFLDMOS晶体管 ,它的击穿电压可由 178V提高到 2 34V ,增加了 1 5倍 ,而比导通电阻却从 7 7mΩ·cm2 下降到 5mΩ·cm2 ,减小了 30 % ,显示了很好的击穿电压和导通电阻折中性能 .

Ⅲ-Ⅴ族三结抗辐照太阳电池结构的改进初探

文章介绍了Ⅲ-Ⅴ族叠层太阳电池抗辐照设计的基本思路,提出了Ⅲ-Ⅴ族叠层抗辐照太阳电池的两种改进结构p-i-n结构和线性掺杂结构,并探讨分析了这两种结构的物理原理和在抗辐照性能上的优劣,为进一步改善其抗辐射效应作了颇有意义的基础工作。

Unified Breakdown Model of SOI RESURF Device with Uniform/Step/Linear Doping Profile

A unified breakdown model of SOI RESURF device with uniform,step,or linear drift region doping profile is firstly proposed.By the model,the electric field distribution and breakdown voltage are researched in detail for the step numbers from 0 to infinity.The critic electric field as the function of the geometry parameters and doping profile is derived.For the thick film device,linear doping profile can be replaced by a single or two steps doping profile in the drift region due to a considerable uniformly lateral electric field,almost ideal breakdown voltage,and simplified design and fabrication.The availability of the proposed model is verified by the good accordance among the analytical results,numerical simulations,and reported experiments.

超薄层SOI高压LVD LDMOS耐压模型及特性研究

针对超薄层高压SOI线性变掺杂(Linear Varied Doping,LVD)LDMOS器件,进行了耐压模型和特性的研究。通过解泊松方程,得到超薄高压SOI LVD LDMOS的RESURF判据,有助于器件耐压和比导通电阻的设计与优化。通过对漂移区长度、厚度和剂量,以及n型缓冲层仿真优化,使器件耐压与比导通电阻的矛盾关系得到良好的改善。实验表明,超薄层高压SOI LVD LDMOS的耐压达到644V,比导通电阻为24.1Ω·mm2,击穿时埋氧层电场超过200V/cm。

薄膜SOI上大于600 V LDMOS器件的研制

针对600 V以上SOI高压器件的研制需要,分析了SOI高压器件在纵向和横向上的耐压原理。通过比较提出薄膜SOI上实现高击穿电压方案,并通过仿真预言其可行性。在埋氧层为3μm,顶层硅为1.5μm的注氧键合(Simbond)SOI衬底上开发了与CMOS工艺兼容的制备流程。为实现均一的横向电场,设计了具有线性渐变掺杂60μm漂移区的LDMOS结构。为提高纵向耐压,利用场氧技术对硅膜进行了进一步减薄。流片实验的测试结果表明,器件关态击穿电压可达600 V以上(实测832 V),开态特性正常,阈值电压提取为1.9 V,计算开态电阻为50Ω.mm2。

一种部分超结型薄层SOI LIGBT器件的研究

基于介质场增强(ENDIF)理论,提出了一种部分超结型薄硅层SOI横向绝缘栅双极型晶体管(PSJ SOI LIGBT)。分析了漂移区注入剂量和超结区域位置对器件耐压性能的影响,并在工艺流程中结合线性变掺杂技术和超结技术,使该器件实现了高垂直方向耐压和低导通电阻。测试结果表明,该器件的耐压达到816 V,比导通电阻仅为12.5Ω·mm^(2)。

Peculiar Nonlinear Depletion in Double-Layered Gated Si-δ-Doped GaAs

The low-temperature measurement of Hall effect of the two-dimensional electron system in a double-layered gated Si-δ-doped GaAs is presented.A complex peculiar nonlinear dependence of the depletion on gate voltage is observed.The nonlinearity is also explained on the basis of the assumption that the double-capacity model consists of two δ-doped two-dimensional electron layers and a metallic gate,and the experimental result that the electron mobility is linear with the electron density on a log-log scale.

Visible-Light Activities of Erbium Doped BiVO4 Photocatalysts

Er-doped BiVO4 composite photocatalyst was hydrothermal synthesized and characterized by X-ray powder diffraction, scanning electron microscopy, energy-dispersive X-ray Spectroscopy, X-ray photoelectron spectroscopy, and UV-Vis diffuse reflectance spectra techniques. The activity of the catalyst was determined by oxidative decomposition of methyl orange in aqueous solution under visible-light irradiation. X-ray photoelectron spectroscopy and energy-dispersive X-ray Spectroscopy analysis revealed that the doped Er existed in the form of Er2O3. It also showed that the Er doping can enhance the visible-light absorption abilities of catalysts and their visible-light-driven photocatalytic activities in comparison with those of pure BiVO4.

Device Characteristics Comparison Between GaAs Single and Double Delta-Doped Pseudomorphic High Electron Mobility Transistors

The Al 0.24Ga 0.76As/In 0.22Ga 0.78As single delta-doped PHEMT (SH-PHEMT) and double delta-doped PHEMT (DH-PHEMT) are fabricated and investigated.Based on the employment of double heterojunction,double delta doped design,the DH-PHEMT can enhance the carrier confinement,increase the electron gas density,and improve the electron gas distribution,which is beneficial to the device performance.A high device linearity,high transconductance over a large gate voltage swing,high current drivability are found in DH-PHEMT.These improvements suggest that DH-PHEMT is more suitable for high linearity applications in microwave power device.

Comparative characteristics of yttrium oxide and yttrium nitric acid doping in ZnO varistor ceramics

The effect of different molar ratios of Y2O3 and Y（NO3）3 on the microstructure and electrical response of ZnO-Bi203-based varistor ceramics sintered at 1 000 ℃ was investigated, and the mechanism by which this doping improves the electrical characteristics of ZnO-Bi203-based varistor ceramics was discussed. With increasing amounts of Y（NO3）3 or Y2O3 in the starting composition, Y2O3, Sb204 and Y-containing Bi-rich phase form, and the average grain size significantly decreases. The average grain size significantly decreases as the contents of rare earth compounds of Y（NO3）3 or Y2O3 increase. The maximum value of the nonlinear coefficient is found at 0.16% Y（NO3）3 or 0.02% YaO3 （molar fraction） doped varistor ceramics, and there is an increase of 122% or 35% compared with the varistor ceramics without Y（NO3）3 or Y2O3. The threshold voltage VT of Y（NO3）3 and Y2O3 reaches at 1 460 V/mm and 1 035 V/ram, respectively. The results also show that varistor sample doped with Y（NO3）3 has a remarkably more homogeneous and denser microstructure in comparison to the sample doped with Y2O3.

线性变掺杂高阻漂移区LDMOS导通电阻的建模

首先建立了线性变掺杂高阻漂移区LDMOS的导通电阻的模型,通过分析、计算,得出它的导通电阻的解析表达式,然后用MATLAB软件和MEDICI软件对总导通电阻和各部分电阻进行模拟。经过讨论,得出其性能优于均匀掺杂高阻漂移区LDMOS的结论。

Influence of Yb_2O_3 doping on microstructural and electrical properties of ZnO-Bi_2O_3-based varistor ceramics

ZnO-Bi2O3-based varistor ceramics doped with Yb2O3 in the range from 0 to 0.4% （molar fraction） were obtained by a solid reaction route. The X-ray diffractometry （XRD） and scanning electron microscopy （SEM） were applied to characterize the phases and microstructure of the varistor ceramics, and a DC parameter instrument for varistor ceramics was applied to investigate their electrical properties and V-I characteristics. The XRD analysis of the samples shows that the ZnO phase, Bi2O3 phase, ZnTSbaOl2-type spinel phase and Zn2Bi3Sb3O14-type pyrochlore are present, and the Yb2O3 phases and Sb2O4 phases are found in varistor ceramics with increasing amounts of Yb2O3. The average size of ZnO grain firstly increases and then decreases with the increase of Yb2O3 content. The result also shows that the threshold voltage is between 656 V/nun and 1 232 V/mm, the nonlinear coefficient is in the range of 14.1-22.3, and the leakage current is between 0.60 μA and 19.6 μA. The 0.20% Yb2O3-added ZnO-Bi2O3-based varistor ceramics sintered at 900 ℃ have the best electrical characteristics.

Nonlinear analysis of nano-cluster doped fiber

There are prominent nonlinear characteristics that we hope for the semiconductor nano-clusters doped fiber. Refractive index of fiber core can be effectively changed by adulteration. This technology can provide a new method for developing photons components. Because the semiconductor nano-cluster has quantum characteristics, Based on first-order perturba- tion theory and classical theory of fiber, we deduced refractive index expressions of fiber core, which was semiconductor nano-cluster doped fiber. Finally, third-order nonlinear coefficient equation was gained. Using this equation, we calculated SMF-28 fiber nonlinear coefficient. The equation shows that new third-order coefficient was greater.

Simulation of High Power Er/Yb Codoped Fiber Linear Cavity Lasers

The performances of high power Er/Yb codoped fiber linear cavity lasers are investigated numerically. The numerical analysis is based on the iterative solution of rate equations for population density of the Er/Yb ions. The behaviors of co-pump and counter-pump methods are contrasted. Dependence of output power on input pump power, output reflectivity, operating wavelength and active fiber length is simulated, respectively. High conversion efficiency Er/Yb laser output is obtained in simulations and experiments.

Structural and Magnetic Properties of Bi（Fe1-xMnx）O3

Bi（Fe1-xMnx）O3 bulk ceramics with Mn concentration x up to 0.3 were prepared by rapid sintering using sol-gel derived fine powders. Structure transformation is found to depend on the Mn doping concentration by X-ray diffraction and Raman spectroscopy. Bi（Fe1-xMnx）O3 maintains the rhombohedral structure of BiFeO3 with x=0.05 and 0.1, but changes to the orthorhombic structure with x=0.3. Weak ferromagnetism is observed for Bi（Fe1-xMnx）O3 with x=0.05 and 0.1, but stronger paramagnetism is observed for Bi（Fe1-xMnx）O3 with x=0.3 indicating a magnetic phase change from antiferromagnetic to paramagnetic with the structure changing from R3c to C222. Two anomalies at 30 and 140 K are observed for Bi（Fe1-xMnx）O3 with x=0.05 and 0.1. The anomaly at 30 K is concluded to be related to the freezing of cluster spin glass from dc magnetic memory and relaxation measurements.

Er^(3+)-Yb^(3+) Co-Doped Fiber Ring and Line Laser

Er3+-Yb3+ co-doped fiber of 2 m long is used as the laser gain medium. Two fiber lasers with different structures have been set up, one is the line cavity fiber laser with the dielectric mirror being replaced by an all-fiber reflecting mirror,the other is the ring cavity all-fiber laser. Both set-ups have achieved lasing operation at the wavelength of 1.53 μm. Pumped by the 1 064 nm light from all-solid-state Nd ∶YAG laser, the two fiber lasers at 1 530 nm are operational. Their output powers are 7.8 mW and 2 mW with 130 mW and 160 mW pump powers.