毫米波脉冲体效应二极管

报导了脉冲输出大于1W的8mm体效应二极管，给出了器件结构和参数设计及其电参数研究。器件最佳性能为36．5GHz下，脉冲输出功率1．5W。用于8mm脉冲锁相放大器中，获得了增益13dB，输出大于0．66W，带宽大于1．5GHz的结果。

谐波提取理论的实践

介绍体效应器件的谐波工作机理和“基波振荡 ,谐波提取”的理论 ,根据该理论完成了 6 mm信号的放大和倍频 ,成功的设计了从 X波段到 3mm波段的八倍频组件 ,大大节约了雷达系统的成本和体积 。

非晶硅薄膜在电子学领域的应用

近年来,a-Si:H薄膜已引起人们很大的兴趣。这不仅是因为非晶态的固体理论问题需要研究,更主要的是因为非晶硅材料具有诱人的应用前景。 在七十年代以前,人们普遍采用真空蒸发法和溅射法来制备非晶硅薄膜。但当时制备的非晶硅薄膜的性质不佳,因而并不特别受人注意。从七十年代中期开始,发展了辉光放电分解沉积的非晶硅制备技术。由这一技术所制备的非晶硅薄膜,具有十分引人注目的光学和电学性质。它和传统的非晶硅的差别在于材料中含有一定量的氢。氢的引入大大地降低了材料中的缺陷态密度。α-Si:H这一新材料的特点可归纳为:

CMOS FinFET Fabricated on Bulk Silicon Substrate

A CMOS FinFET fabricated on bulk silicon substrate is demonstrated.Besides owning a FinFET structure similar to the original FinFET on SOI,the device combines a grooved planar MOSFET in the Si substrate and the fabrication processes are fully compatible with conventional CMOS process,including salicide technology.The CMOS device,inverter,and CMOS ring oscillator of this structure with normal poly silicon and W/TiN gate electrode are fabricated respectively.Driving current and sub threshold characteristics of CMOS FinFET on Si substrate with actual gate length of 110nm are studied.The inverter operates correctly and minimum per stage delay of 201 stage ring oscillator is 146ps at V d=3V.The result indicates the device is a promising candidate for the application of future VLSI circuit.

Development of Novel Thin-Film SOI High Voltage MOSFET

Two kinds of thin-film SOI high voltage MOSFETs are developed.One is general structure,the other is novel two-drift-region structure.The gate width is 760μm,and the active area is 8.58×10 -2 mm 2.The experiments show that the breakdown voltages of the two-drift-region and general structures are 26V and 17V,respectively,and the on resistances are 65Ω and 80Ω,respectively.

Floating Body Effect in Partially Depleted SOI nMOSFET with Asymmetric Structure and Ge-Implantation

The floating body effect of an asymmetric and Ge implanted partially depleted 0 8μm SOI nMOSFET is investigated.It is found that the drain breakdown voltage can be improved by about 1V and that the anomalous subthreshold slope and kink effect are also lessened.It is believed that the shallow junction in the source and defect states introduced by Ge implantation are responsible for the reduction of the floating body effect.

Optimization Design and Fabrication of Si/SiGe PMOSFETs

Through the theoretical analysis and computer simulation,the optimized design principles for Si/SiGe PMOSFETs are given,including the choice of gate materials,the determination of Ge percentage and the profile in SiGe channel,the thickness optimization of dioxide and silicon cap layer,and the adjustment of threshold voltage.In light of them,a SiGe PMOSFET is designed and fabricated successfully.The measurements indicate that the transconductance is 45mS/mm (300K) and 92mS/mm (77K) for SiGe PMOSFET's (L=2μm),while it is 33mS/mm (300K) and 39mS/mm (77K) for Si PMOSFET.

Simulation of Gate-All-Around Cylindrical Transistors for Sub-10 Nanometer Scaling

A gate-all-around cylindrical （GAAC） transistor for sub-10nm scaling is proposed. The GAAC transistor device physics,TCAD simulation,and proposed fabrication procedure are reported for the first time. Among all other novel FinFET devices, the gate-all-around cylindrical device can be particularly applied for reducing the problems of the conventional multi-gate FinFET and improving the device performance and the scale down capability. According to our simulation,the gate-all-around cylindrical device shows many benefits over conventional multi-gate FinFET, including gate-all- around rectangular （GAAR） devices. With gate-all-around cylindrical architecture,the transistor is controlled by an essen- tially infinite number of gates surrounding the entire cylinder-shaped channel. The electrical integrity within the channel is improved by reducing the leakage current due to the non-symmetrical field accumulation such as the corner effect. The proposed fabrication procedures for devices having GAAC device architecture are also discussed. The method is characterized by its simplicity and full compatibility with conventional planar CMOS technology.

Low voltage n-type OFET based on double insulators

A top contact n-type organic field-effect transistor with low operating voltage was fabricated by employing Ta2O5/PMMA as the double insulators and PTCDI-Cl2 as the semiconductor active layer. The Ta2O5 layer was prepared by using simple economical anodization technique and the PMMA layer was prepared by using the spin-coating method. Compared with the OFET with single Ta2O5 insulator, the device with double insulators shows obviously better electrical performance. It has a field effect electron mobility of 0.063 cm^2/Vs, an on/off ratio of 1.7 × 10^4 and a threshold voltage of 2.3 V.

RESEARCH OF BJMOSFET FREQUENCY CHARACTERISTICS

The parasitic capacitance effect and its influence to the performance have been investigated in Bi-polar Junction Metal-Oxide-Semiconductor Field-Effect Transistor (BJMOSFET). The frequency characteristic equivalent circuit and high frequency response model of BJMOSFET have been presented. The frequency characteristic of BJMOSFET is simulated using the multi-transient analytical method and PSPICE9 simulator. The conclusions that BJMOSFET owns less total capacitance, wider frequency band, better transient charac-teristic and better frequency responses are reached by comparing with the traditional MOSFET at the same structure parameters and bias conditions. BJMOSFET, as a novel promising high frequency device, would be desired to find application in future integrated circuit.

Quantum-Mechanical Study on Surrounding-Gate Metal-Oxide-Semiconductor Field-Effect Transistors

As the channel length of metal-oxide-semiconductor field-effect transistors （MOSFETs） scales into the nanometer regime, quantum mechanical effects are becoming more and more significant. In this work, a model for the surrounding-gate （SG） nMOSFET is developed. The SchrSdinger equation is solved analytically. Some of the solutions are verified via results obtained from simulations. It is found that the percentage of the electrons with lighter conductivity mass increases as the silicon body radius decreases, or as the gate voltage reduces, or as the temperature decreases. The eentroid of inversion-layer is driven away from the silicon-oxide interface towards the silicon body, therefore the carriers will suffer less scattering from the interface and the electrons effective mobility of the SG nMOSFETs will be enhanced.

High-resolution flexible electronic devices by electrohydrodynamic jet printing:From materials toward applications

High-resolution flexible electronic devices are widely used in the fields of soft robotics,smart human-machine interaction,and intelligent e-healthcare monitoring due to their mechanical flexibility,ductility,and compactness.The electrohydrodynamic jet printing(e-jet printing)technique is used for constructing high-resolution and cross-scale flexible electronic devices such as field-effect transistors(FETs),flexible sensors,and flexible displays.As a result,researchers are paying close attention to e-jet printing flexible electronic devices.In this review,we focused on the latest advancements in high-resolution flexible electronics made by e-jet printing technology,including various materials used in e-jet printing inks,the process control of e-jet printing,and their applications.First,we summarized various functional ink materials available for e-jet printing,including organic,inorganic,and hybrid materials.Then,the interface controlling the progress of e-jet printing was discussed in detail,including the physical and chemical properties of the functional ink,the interfacial wettability between the ink and substrate,and the microdroplet injection behavior in a high-voltage field.Additionally,various applications of e-jet printing in the fields of flexible electrodes,FETs,flexible sensors,and flexible displays were demonstrated.Finally,the future problems and potential associated with the development of next generation e-jet printing technology for flexible electronic devices were also presented.

Controlled one step thinning and doping of twodimensional transition metal dichalcogenides

Two-dimensional(2 D) transition metal dichalcogenides(TMDCs) have drawn intensive attention due to their ultrathin feature with excellent electrostatic gating capability, and unique thickness-dependent electronic and optical properties. Controlling the thickness and doping of 2 D TMDCs are crucial toward their future applications. Here, we report an effective HAu Cl4 treatment method and achieve simultaneous thinning and doping of various TMDCs in one step. We find that the HAu Cl4 treatment not only thins thick Mo S2 flakes into few layers or even monolayers, but also simultaneously tunes Mo S2 into p-type. The effects of various parameters in the process have been studied systematically,and an Au intercalation assisted thinning and doping mechanism is proposed. Importantly, this method also works for other typical TMDCs, including WS2, Mo Se2 and WSe2,showing good universality. Electrical transport measurements of field-effect transistors(FETs) based on Mo S2 flakes show a big increase of On/Off current ratios(from 102 to 107) after the HAu Cl4 treatment. Meanwhile, the subthreshold voltages of the Mo S2 FETs shift from-60 to +27 V after the HAu Cl4 treatment, with a p-type doping behavior. This study provides an effective and simple method to control the thickness and doping properties of 2 D TMDCs, paving a way for their applications in high performance electronics and optoelectronics.

Organic transistor for bioelectronic applications

Organic field-effect transistors(OFETs) are recently considered to be attractive candidate for bioelectronic applications owing to their prominent biocompatibility,intrinsical flexibility,and potentially low cost associated with their solution processibility.Over the last few years,bioelectronic-application-motivated OFETs have attracted increasing attention towards next generation of biosensors,healthcare elements and artificial neural interfaces.This mini review highlights the basic principles and recent progress in OFET based bioelectronics devices.The key strategies and the forecast perspectives of this research field are also briefly summarized.

Effects of gate dielectric thickness and semiconductor thickness on device performance of organic field-effect transistors based on pentacene

In this paper,the pentacene-based organic field-effect transistors(OFETs)with poly(methyl methacrylate)(PMMA)as gate dielectrics were fabricated,and the effects of gate dielectric thickness and semiconductor thickness on the device performance were investigated.The optimal PMMA thickness is in the range of 350–400 nm to sustain a considerable current density and stable performance.The device performance depends on the thicknesses of the active layer non-monotonically,which can be explained by the morphology of the pentacene film and the position of the conducting channel in the active layer.The device with a pentacene thickness of 50 nm shows the best performance,which has a maximum hole mobility of 1.12 cm2/V·s.In addition,the introduction of a thin layer of tris-(8-hydroxyquinolinato)aluminum(Alq3)to the OFETs as a light-emitting material greatly decreases the device performance.

A Sixth-Order Parabolic System in Semiconductors

The authors investigate the global existence and semiclassical limit of weak solutions to a sixth-order parabolic system,which is a quantum-corrected macroscopic model derived recently to simulate the quantum effects in miniaturized semiconductor devices.