离子径迹电光学性质的太赫兹时域光谱

为了深入研究离子径迹的电光学性质,室温下用太赫兹时域光谱（THz-TDS）测量高能重离子辐照的聚苯乙烯（PS）和聚乙烯（PE）,获得了辐照样品的光学常数。研究发现,在离子沉积能量或离子剂量较高时,辐照PS和PE的吸收系数相比未辐照样品都有显著增加,这是由于辐照产生的碳团聚体对太赫兹波有吸收作用;对折射率而言,辐照PS的折射率增加而辐照PE的折射率降低,这与2种聚合物的结构有关。用有效介质理论提取出辐照聚合物中离子径迹的光学常数,并用Drude-Lorentz模型对其进行拟合,由拟合参数计算出了离子径迹的直流电导率。与常规接触测量法获得的离子径迹的电学参数进行比较,发现2种测量结果的差异是由于沿径迹方向能量沉积的不均匀性造成,THz-TDS测量结果更能反映高能量沉积区域物质的电学性质。     

注F~+加固CMOS/SOI材料的抗辐射研究

向SIMOX材料的SiO2埋层或Si/SiO2界面注入170 keV F+,进而制成CMOS/SOI材料,采用60Co g 辐射器辐照并测量材料的I-V特性。结果表明:向CMOS/SOI材料埋层注入F+离子,能提高CMOS/SOI材料的抗电离辐照性能。而且,注入F+的剂量为11015cm2时,材料的抗辐照能力较强。这对制作应用于电离辐射环境的COMS/SOI器件极其有益。     

部分耗尽型注氟SIMOX器件的电离辐射效应

采用在SIMOX圆片埋氧层中注入氟(F)离子的方法改善SIMOX的抗总剂量辐射能力,通过比较未注F样品和注F样品辐照前后SIMOX器件Ids-Vgs特性和阈值电压,发现F具有抑制辐射感生pMOSFET和nMOSFET阈值电压漂移的能力,并且可以减小nMOSFET中由辐照所产生的漏电流.说明在SOI材料中前后Si/SiO2界面处的F可以减少空穴陷阱密度,有助于提高SIMOX的抗总剂量辐射能力.     

Si3N4栅MOS器件的隧穿电流模拟

随着MOS器件尺寸按比例缩小到亚100 nm时代,栅绝缘层直接隧穿(Direct Tunnel-ing,DT)电流逐渐增大.使用Si3N4材料作为栅介质,利用其介电常数高于SiO2的特性,可以在一定时期内有效地解决隧穿电流的问题.文章在二维器件模拟软件PISCES-II中首次添加了模拟高k材料MOS晶体管的器件模型,并对SiO2和Si3N4栅MOS晶体管的器件特性进行了模拟比较.     

一种新型抗辐照SOI隔离结构

制备了一种新型抗辐照SOI隔离结构,它包含了薄SiO2/多晶硅/SiO2多层膜.利用这种结构制备的SOI器件在经受3×105rad(Si)的辐照后亚阈值特性未发生明显变化,漏电流也无增加,说明其抗辐照性能优于传统的LOCOS隔离结构.     

High-k材料MOS器件的PISCES-II模拟

High-k材料是指介电常数k高于SiO2的材料。使用high-k材料做栅绝缘层,是减小MOS器件栅绝缘层直接隧道击穿(DirectTunneling,DT)电流的有效方法。文章在二维器件模拟软件PISCES-II中添加了模拟以high-k材料为栅绝缘层的MOS器件模型,并对SiO2和high-k材料的MOS晶体管器件特性进行了模拟比较,成功地验证了所加high-k材料MOS器件模型的正确性。改进后的PISCES-II程序,可以方便地对以各种high-k材料为栅绝缘层的器件性能进行模拟。     

一种新型抗辐照SOI隔离结构

制备了一种新型抗辐照SOI隔离结构，它包含了薄SiO2/多晶硅/SiO2多层膜．利用这种结构制备的SOI器件在经受3×１０~5rad(Si)的辐照后亚阈值特性未发生明显变化，漏电流也无增加，说明其抗辐照性能优于传统的LOCOS隔离结构．     

预先老化对注F nMOS器件辐射可靠性的影响

对注F和未注F CC4007器件在100℃高温老化后的Co60辐照特性进行了研究.研究发现辐照前的高温老化减少了注F器件在辐照中的界面态陷阱电荷的积累,但是普通器件辐照前的高温老化在减少辐照中界面态积累的同时却增加了氧化物电荷的积累,损害了器件的可靠性.可见,栅介质中F离子的引入可以明显提高器件的可靠性.     

预先老化对注F nMOS器件辐射可靠性的影响

对注F和未注F CC4007器件在100℃高温老化后的Co60辐照特性进行了研究．研究发现辐照前的高温老化减少了注F器件在辐照中的界面态陷阱电荷的积累,但是普通器件辐照前的高温老化在减少辐照中界面态积累的同时却增加了氧化物电荷的积累,损害了器件的可靠性．可见,栅介质中F离子的引入可以明显提高器件的可靠性．     

High-k材料MOS器件的PISCES-Ⅱ模拟

High-k材料是指介电常数k高于SiO2的材料。使用Hihg-k材料做栅绝缘层，是减小MOS器件栅绝缘层直接隧道击穿（Direct Tunneling,DT)电流的有效方法。文章在二维器件模拟软件PISCES－Ⅱ中添加了模拟以high-k材料为栅绝缘层的MOS器件模型，并对SiO2和high-k材料的MOS晶体管器件特性进行了模拟比较，成功地验证了所加high-k材料MOS器件模型的正确性，改进后的PISCES－Ⅱ程序，可以方便地对以各种high-k材料为栅绝缘层的器件性能进行模拟。     

Stability of submicron AlGaN/GaN HEMT devices irradiated by gamma rays

AlGaN/GaN high electron mobility transistors (HEMTs) with 0.75 μm gate-length and incorporated C-doped GaN buffer layers have been exposed to gamma radiation. The devices have been irradiated to cumulative doses up to 10⁷ rad. The effect of gamma irradiation on the direct current (DC) and low-frequency noise properties of these devices have been investigated in reference to the unexposed device. The DC and noise characteristics show deteriorating device performance upon the gamma exposure. However, some DC parameters, such as transconductance, tended to recover after the irradiation. The gate leakage current and low-frequency noise power spectra indicate this trend even couple of months after the irradiation.     

HDMI接口的ESD防护设计

HDMI 1．3中实现了较高的分辨率和像素深度,集成电路制造商已经持续地缩小了它们的器件中的晶体管、互连和SiO2绝缘层的尺寸,这就导致高速器件的结构更小．因而在较低的能级也易于受到击穿效应的破坏。在发生ESD的时候,SiO2层很可能断裂,金属线很可能开路或桥接。     

CMOS／SIMOX和CMOS／BESOI的γ射线辐照特性比较

用薄膜ＳＩＭＯＸ（ＳｅｐａｒａｔｉｏｎｂｙＩＭｐｌａｎｔａｔｉｏｎｏｆＯＸｙｇｅｎ）、厚膜ＢＥＳＯＩ（ｆｆｅｎｄｉｎｇａｎｄＥｔｃｈ－ｂａｃｋＳｉｌｉｃｏｎＯｎＩｎｓｕｌａｔｏｒ）和体硅材料制备了ＣＭＯＳ倒相器电路，并用６０Ｃｏγ射线进行了总剂量辐照试验。在不同偏置条件下，经不同剂量辐照后，分别测量了ＰＭＯＳ、ＮＭＯＳ的亚阈特性曲线，分析了引起ＭＯＳＦＥＴ阈值电压漂移的两种因素（辐照诱生氧化层电荷和新生界面态电荷）。对ＮＭＯＳ／ＳＩＭＯＸ，由于寄生背沟ＭＯＳ结构的影响，经辐照后背沟漏电很快增大，经３００Ｇｙ（Ｓｉ）辐照后器件已失效。而厚膜ＢＥＳＯＩ器件由于顶层硅膜较厚，基本上没有背沟效应，其辐照特性优于体硅器件。最后讨论了提高薄膜ＳＩＭＯＸ器件抗辐照性能的几种措施。     

Impact of Device Layout and Annealing Process During the Passivation of Interface States in Presence of Silicon Nitride Layers

This paper reports the experimental evidence of anomalous electrical characteristics of large test structures for the characterization of both silicon–oxide–nitride–oxide–silicon (SONOS) and MOS gate stacks featuring nitride caps. The anomaly has been studied on devices featuring different layouts and it has been attributed to the property of silicon nitride layers to block the diffusion of hydrogen used for the passivation of the Si/${hbox{SiO}}_{2}$ interface dangling bonds. Since the hydrogen passivation can occur only from the lateral sides of the device, our findings imply restrictions on the dimensions and on the layout of the test structures used to study the electrical properties of the gate stacks in SONOS or in large MOS devices featuring protective nitride caps.      

PMOS transistors fabricated in large-area laser-crystallised Si on silica

PMOS transistors have been fabricated in device-worthy Si which was achieved by large-area laser-crystallisation of Si on silica. The crystallised Si contains few large-angle grain boundaries due to laser-beam inhomogeneity but exhibits subgrain boundaries aligned along the laser track. Cracking of the Si, a result of the mismatch of the thermal expansion coefficients of Si and silica, has been substantially reduced by removing only a stripped region of the SiO2 encapsulation layer for transistor fabrication. A high yield and good electrical characteristics of the devices were obtained.     

高阻硅中深能级与少子寿命的研究

本文测量了ｎ型高阻硅在９种不同浓度的金掺杂前后少子寿命的变化，以及两类不同电阻率的ｎ型高阻硅在７种不同辐照剂量的１ＭｅＶ高能电子辐照前后少子寿命的变化；测量了金掺杂和高能电子辐照在硅中引入的主要深能级；研究对比金掺杂和高能电子辐照对硅单晶性能的影响及其在提高电子器件开关速度方面的应用。     

Electron irradiation of field-controlled thyristors

The influence of 3-MeV electron irradiation upon the characteristics of asymmetrical field-controlled thyristors has been examined for fluences of up to 16 Mrad. In addition to the lifetime reduction due to the radiation damage, carrier removal effects have also been observed in the very lightly doped n-base region of these devices. The leakage current, even after radiation at the highest fluenee, is not significantly increased and the blocking characteristies of these devices are not degraded. In fact, a small improvement in the blocking gain has been observed at low gate voltages. The electron irradiation has been found to increase the forward voltage drop during current conduction and to reduce the forced gate turn-off time. Gate turn-off times of less than 500 ns have been achieved by irradiation with a fluence of 16 Mrad. However, this is accompanied by a large increase in the forward voltage drop. Tradeoff curves between the forward voltage drop and the gate turn-off time have been obtained. From these curves, it has been determined that gate turnoff times of 1 µs can be obtained without a significant increase in the forward voltage drop for devices capable of blocking up to 600 V.     

今日SiC电子学

ＳｉＣ是近几年迅速发展的一种半导体材料,在微波功率器件、功率电子开关器件、高温工作器件等方面比Ｓｉ和ＧａＡｓ具有更大的优势。本文介绍了ＳｉＣ材料特性、材料制备及目前器件研制水平。     

Steady‐State and Transient Behavior of Organic Electrochemical Transistors

In recent years, organic electrochemical transistors (OECTs) have emerged as attractive devices for a variety of applications, particularly in the area of sensing. While the electrical characteristics of OECTs are analogous to those of conventional organic field effect transistors, appropriate models for OECTs have not yet been developed. In particular, little is known about the transient characteristics of OECTs, which are determined by a complex interplay between ionic and electronic motion. In this paper a simple model is presented that reproduces the steady‐state and transient response of OECTs by considering these devices in terms of an ionic and an electronic circuit. A simple analytical expression is derived that can be used to fit steady‐state OECT characteristics. For the transient regime, comparison with experimental data allowed an estimation of the hole mobility in poly(3,4‐ethylenedioxythiophene) doped with poly(styrene sulfonate). This work paves the way for rational optimization of OECTs.     

储能电容器在大电流脉冲系统中的应用

储能电容器是一种容纳大容量电荷的电子器件。脉冲工作时,储能电容器作为储能器件,可提供超大的电流能力;利用储能电容器的充放电特性,可以将电子系统中脉冲电流滤波成为较为平滑的直流电,大大降低低压大电流脉冲电子系统对电源的要求。本文给出了低压脉冲系统中储能电容器使用原则和高分三号卫星中应用实例,通过对卫星供电系统建模仿真,得出了系统最优的电容使用参数。文中的设计方法对其他电子系统设计具有一定的借鉴意义。