中子辐照的单晶硅参数研究

在不同温度和红外光照下，测量了经中子辐照的单晶硅表面光电压，确定了其深能级的位置和少子扩散长度；由双能级复合理论，推导了中子辐照单晶硅的深能级复合中心和寿命的计算公式；计算了热中子辐照和高能中子辐照单晶硅后的深能级密度、费米能级和其他有关重要参数。     

离子注入和脉冲激光退火制备碲超饱和掺杂单晶硅pn结

Pn junctions based on single crystalline tellurium supersaturated silicon were formed by ion implantation followed by pulsed laser melting（PLM）.P type silicon wafers were implanted with 245 keV ¹²⁶Te⁺ to a dose of 2×10¹⁵ ions/cm²,after a PLM process（248 nm,laser fluence of 0.30 and 0.35 J/cm²,1-5 pulses,duration 30 ns）,an n⁺ type single crystalline tellurium supersaturated silicon layer with high carrier density(highest concentration 4.10×10¹⁹ cm^-3,three orders of magnitude larger than the solid solution limit) was formed,it shows high broadband optical absorption from 400 to 2500 nm.Current-voltage measurements were performed on these diodes under dark and one standard sun（AM 1.5）,and good rectification characteristics were observed.For present results,the samples with 4-5 pulses PLM are best.     

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．     

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.     

SOI材料与器件的辐照效应

目前，ＳＯＩ（ＳｉｌｉｃｏｎＯｎＩｎｓｕｌａｔｏｒ）材料的一个主要用途是用来制作抗辐照电路，本文以ＳＩＭＯＸ（ＳｅｐｅｒａｔｉｏｎｂｙＩＭｐｌａｎｔａｔｉｏｎｏｆＯＸｙｇｅｎ）技术为主，详细论述了ＳＯＩ材料和器件（ＭＯＳＦＥＴ）的辐照特性及其机理，包括总剂量、瞬时和单粒子效应，并以总剂量效应为主。经过恰当的加固工艺和优化设计，可以制造出优良的抗辐照集成电路。     

中子嬗变掺杂单晶硅的电学性能研究

本工作用霍尔系数-电阻率测量,研究了不同原始单晶硅和掺杂温度对NTD Si在高温退火过程中电学性能回复的影响。本文给出了几种NTD Si的自由载流子浓度和迁移率的等时退火曲线和各种特征温度,并对实验结果作了简要讨论。     

抗中子辐照器件结构参数的确定

本文分析了高压二极管、低频功率晶体管等器件在中子辐照后电参数退化规律。为提高这些器件的耐中子辐照能力,给出了这些器件结构参数的设计要求,以及这种结构特点的器件设计中需注意的有关问题。     

单晶硅中氢与辐照缺陷的相互作用

对NTD氢区熔单晶硅进行了不同温度下等时退火,采用Hall电学方法测量了电阻率、迁移率随退火温度的变化规律.利用红外吸收技术测量了单晶硅氢区熔退火前后及NTD氢区熔单晶硅不同退火温度下与氢、辐照缺陷有关的红外振动吸收峰变化,对辐照缺陷的退火行为进行了探讨.实验证实NTD氢区熔单晶硅在150～650℃范围内等时退火具有显著特点:在500℃下退火,出现电阻率极小值,即出现浓度很高的过量浅施主;P型向N型转变温度为400℃,迁移率恢复温度为500℃,载流子恢复温度为600℃,均明显低于NTD氩区熔单晶硅转型温度及迁移率和载流子恢复温度,这与氢积极参与辐照缺陷相互作用直接相关.     

单晶硅中氢与辐照缺陷的相互作用

对NTD氢区熔单晶硅进行了不同温度下等时退火,采用Hall电学方法测量了电阻率、迁移率随退火温度的变化规律.利用红外吸收技术测量了单晶硅氢区熔退火前后及NTD氢区熔单晶硅不同退火温度下与氢、辐照缺陷有关的红外振动吸收峰变化,对辐照缺陷的退火行为进行了探讨.实验证实NTD氢区熔单晶硅在150～650℃范围内等时退火具有显著特点:在500℃下退火,出现电阻率极小值,即出现浓度很高的过量浅施主;P型向N型转变温度为400℃,迁移率恢复温度为500℃,载流子恢复温度为600℃,均明显低于NTD氩区熔单晶硅转型温度及迁移率和载流子恢复温度,这与氢积极参与辐照缺陷相互作用直接相关.     

双极型晶体管中子辐照研究

航天技术的飞速发展对电子系统的固体化、小型化提出越来越高的要求。在宇宙空间工作的电子器件将受到各种射线及高能粒子的辐照。本文主要研究双极型晶体管在高能中子辐照下电参数的变化情况及提高器件抗中子辐照能力的措施。     

LASOS—laser annealed silicon on sapphire

Laser annealing techniques were successfully incorporated into standard MOS/SOS processing to increase transistor channel mobility and processing yield. Silicon islands were photolithographically defined and chemically etched (by KOH) on standard SOS wafers. The islands were exposed to radiation from an excimer laser (λ = 2490 Å) having a pulse duration of 25 ns, a beam size in the range of 0.1-0.2 cm², and an energy density in the range of 0.5 - 1.0 J/cm². Using standard processing techniques MOS transistors were fabricated and characterized. It was found that exposure at an energy density of ∼0.80 J/cm²results in rounding the Si island edges, thus eliminating the "V"-shaped groove profile of the gate oxide and improving Al step coverage. The electrical characteristics of MOS transistors fabricated over laser annealed islands exhibited a 30-percent increase in channel mobility with a small negative shift (<0.2 V) in the transistor threshold voltage.     

An investigation of laser annealed and metal-induced crystallizedpolycrystalline silicon thin-film transistors

We report results on thin-film transistors (TFTs) made from a new hybrid process in which amorphous silicon (a-Si) is first converted to polycrystalline silicon (poly-Si) using Ni-metal-induced lateral crystallization (MILC), and then improved using excimer laser annealing (laser MILC or L-MILC). With only a very low shot laser process, we demonstrate that laser annealing of MILC material can improve the electron mobility from 80 to 170 cm²/Vs, and decrease the minimum leakage current by one to two orders of magnitude at a drain bias of 5 V. Similar trends occur for both p- and n-type material. A shift in threshold voltage upon laser annealing indicates the existence of a net positive charge in Ni-MILC material, which is neutralised upon laser exposure. The MILC material in particular exhibits a very high generation state density of ~10¹⁹ cm^-3 which is reduced by an order of magnitude in L-MILC material. The gate and drain field dependences of leakage current indicate that the leakage current in MILC transistors is related to this high defect level and the abruptness of the channel/drain junction. This can be improved with a lightly doped drain (LDD) implant, as in other poly-Si transistors     

Bulk growth of single crystal silicon carbide

Silicon carbide (SiC) is a promising wide bandgap semiconductor material particularly suitable for future high power devices operable at high temperatures (>200 °C), at high frequencies, and in harsh environments (chemical and radiation) due to its unique physical and crystallographic properties. The absence of SiC liquid phase, under easily achievable growth conditions of pressure and temperature has created unique challenges for crystal growers.This paper reviews the basics of bulk growth processes, including source sublimation, mass transport of the Si and C species to the growing seed and crystallization. The growth process is shown to be a self-congruent phenomenon where the mass transport of the vapor species and the heat dissipation at the surface of phase transformation are interrelated. This process results in reduction of the growth velocity as a function of crystal thickness. Major mechanisms of defect generation in the grown crystal are discussed.     

SOI技术特点及晶圆材料的制备

随着微电子技术发展,要使器件水平进一步提高,除了进一步缩小芯片的特征尺寸外,采用新型材料也是有效的方法。文章介绍了SOI解决方案,阐述了SOI器件与体硅器件相比具有的明显优点。文章重点介绍了SOI晶圆材料的制备方法,目前广泛使用且较有发展前途的SOI的材料制备方法主要有注氧隔离的SIMOX（Seperation by Impolanted Oxygen）方法、硅片键合和反面腐蚀的BESOI（Bonding-Etchback SOI）方法、将键合与注入相结合的Smart Cut SOI方法。指出了SOI很有可能成为今后高性能和高可靠集成电路材料的主流。     

Manufacturability of single and double-gate ultrathin silicon filmfully depleted SOI technologies

Of several possible devices that can be used for sub-70 nm node technologies, two are built on ultra thin SOI layers. Scaling of such thin silicon layer SOI devices is constrained by the severe short channel control problem. To alleviate this, double-gate structures have been proposed by Wong et al. (1999), Chang et al. (2000), and Ieong et al. (2000). In this paper, we assess the manufacturability of single-gate (SG) and symmetric double-gate (DG) devices for gate lengths between 15 and 70 nm. Our results show that SG devices are not only manufacturable but also have tighter distributions than DG devices; inverter ring oscillator (RO) stage delays and power consumption are also better for SG devices. Besides gate length we find two additional major sources of variation: silicon thickness and encapsulation width. We show that for an optimized double-gate device with minimized parasitic resistance, CD variations become a dominant factor at 20-nm gate lengths despite superior electrostatic integrity. Also, the work function of metal gates must be controlled to better than ±0.1 eV (3σ) to avoid severe manufacturability problems     

Fabrication of a GaAs-AlGaAs GRIN-SCH SQW laser diode on silicon by epitaxial lift-off

The epitaxial liftoff (ELO) of a GaAs-AlGaAs graded-index separate-confinement-heterostructure (GRIN-SCH) single-quantum-well (SQW) laser diode and the subsequent transfer to a Si substrate are described. It is the first time that a layer structure containing Al/sub 0.60/Ga/sub 0.40/As has been lifted off, and the 5- mu m thin film was cleaved after ELO by a novel process, called wedge-induced facet cleaving (WFC). The pulsed operation performance of the ELO WFC laser was similar to that of conventionally processed GRIN-SCH SQW lasers. These results hold promise for integrating III-V short-cavity lasers on arbitrary substrates.<>     

氩离子激光泵浦的Nd:YAG单晶光纤激光器

本文报道了以氩离子激光作泵浦源的Nd:YAG单晶光纤激光器的研究结果。获得了波长为1.064μm基模的连续激光输出。其斜率效率高于20％;最高激光输出达35mW。实验结果与理论计算基本吻合     

全耗尽SOI MOSFET及CMOS／SOI电路的研究

采用ＳＩＭＯＸ材料，研制了一种全耗尽ＣＭＯＳ／ＳＯＩ模拟开关电路，研究了全耗尽ＳＯＩ ＭＯＳ场效应晶体管的阈值电压与背栅偏置的依赖关系，对漏源击穿的Ｓｎａｐｂａｃｋ特性进行分析，介绍了薄层ＣＭＯＳ／ＳＩＭＯＸ制作工艺，给出了全耗尽ＣＭＯＳ／ＳＯＩ电路的测试结果。