拉通型硅基APD保护环工艺研究

研究了离子注入后推结与扩散两种掺杂方式制作保护环对拉通型硅基雪崩光电二极管(Si-APD)器件成品率的影响,对比在不同工艺条件下器件反向击穿电压、暗电流的变化情况.研究结果表明,采用离子注入后推结的方式,在注入后3 h@1 100℃条件下的成品率为94％;采用扩散掺杂方式,器件成品率不超过65％.两种方式对器件反向击穿电压影响较小且暗电流抑制效果相当.离子注入后推结制备保护环的方式更适合Si-APD制程.     

在多晶硅掺杂/活化处理过程中栅氧化层的性能退化

在MOS电路制作中,掺杂多晶硅膜的应用已经成为非常重要的半导体技术之一。但是,本文将描述多晶硅掺杂/活化处理过程中产生的缺陷可以严重地影响栅氧化物的性能。无论是否采用离子注入,多晶硅的原位掺杂剂淀积,或旋转源扩散到多晶硅等方法进行掺杂处理,采用150～400(?)的栅氧化物腐蚀的电容器,其成品率都随着掺杂剂浓度的增加,活化温度的升高以及活化时间的增长而愈来愈降低。在重掺杂多晶硅中,对于亚微米CMOS栅工艺,在栅氧化物内,经BF_2~ 或As自对准源/漏注入和活化后,其缺陷密度被证明是接近于10cm~(-2)。另一方面,在低剂量注入和活化后,如用于硅化物多栅工艺,缺陷密度仅仅为0.002cm~(-2)。这些结果对于兆位存贮元件的成品率可能有很大影响。     

不同工艺制备的GaAs MESFET阈值电压均匀性研究

分别采用离子注入隔离凹栅工艺、自隔离平面工艺、离子注入隔离平面工艺在非掺杂半绝缘GaAs衬底上制备MESFET,对三种工艺制备的MESFET的阈值电压均匀性进行了研究。结果表明,器件工艺对MESFET阈值电压有一定的影响,开展GaAs MESFET阈值电压均匀性研究应采用适宜的工艺,以尽可能减少工艺引起的偏差。     

不同工艺制备的GaAs MESFET阈值电压均匀性研究

分别采用离子注入隔离凹栅工艺、自隔离平面工艺、离子注入隔离平面工艺在非掺杂半绝缘 Ga As衬底上制备 MESFET,对三种工艺制备的 MESFET的阈值电压均匀性进行了研究。结果表明 ,器件工艺对 MESFET阈值电压有一定的影响 ,开展 Ga As MESFET阈值电压均匀性研究应采用适宜的工艺 ,以尽可能减少工艺引起的偏差。     

厚多晶硅膜饱和掺杂工艺研究

文章主要介绍了通过对厚多晶硅膜进行饱和掺杂来制作低阻值多晶电阻的方法。分析了多晶硅掺杂扩散模式,其中A类扩散模式能够得到较低的多晶电阻。要使杂质以A类扩散模式掺入多晶硅中,需要采用炉管扩散的方式进行长时间的掺杂。受杂质固溶度影响,一定厚度的掺杂多晶硅电阻值是无法无限制降低的,要制作低阻值多晶电阻,需要淀积厚多晶硅薄膜。文章选择炉管扩散的方式,进行低阻值的多晶硅薄膜制作,并通过实验,证实该方法可以得到稳定、均匀、低阻值的多晶硅方块电阻。     

选择性外延隔离P^＋多晶硅栅PMOSFET

在离子注入埋层的硅片上,以SiO_2层为掩膜和隔离,生长了选择性外延(SEG)单晶硅层,并在此外延层上制作了P~+掺杂的多晶硅栅PMOSFET。浅源漏结的P~+多晶硅栅PMOSFET是使用一次离子注入同时完成栅与源漏的掺杂注入,并由低温退火与快速热退火完成杂质的再分布推进。测试结果表明PMOSFET的短沟道效应明显减小。     

在不同的推进气氛中硼与磷对二氧化硅层的穿通扩散

据研究发现,当采用掺杂多晶硅作为扩散源时,硼与磷会扩散到热生长二氧化硅层中去,这种扩散的快慢与推进气氛有关,在氢气中扩散最快。根据双边界扩散模型,我们计算出了扩散系数。硼在二氧化硅中的扩散系数比磷大约要大两个数量级。这点对于硅栅工艺来说非常重要。在 P 沟硅栅晶体管中.由于硼从掺杂多晶硅栅电极扩散到栅氧化层中去,从而会引起晶体管性能的不稳定。     

CCD栅介质工艺对多晶硅层间介质的影响

CCD多晶硅交叠区域绝缘介质对成品率和器件可靠性具有重要的影响.采用扫描电子显微镜和电学测试系统研究了CCD栅介质工艺对多晶硅层间介质的影响.研究结果表明:栅介质工艺对多晶硅层间介质形貌具有显著的影响.栅介质氮化硅淀积后进行氧化,随着氧化时间延长,靠近栅介质氮化硅区域的多晶硅层间介质层厚度增大.增加氮化硅氧化时间到320 min,多晶硅层间薄弱区氧化层厚度增加到227 nm.在前一次多晶硅氧化后淀积一层15 nm厚氮化硅,能够很好地填充多晶硅层间介质空隙区,不会对CCD工作电压产生不利的影响.     

不同源漏掺杂方式对CCD放大器的影响

通过对CCD片上放大器不同源漏掺杂条件、方块电阻、接触电阻、有效沟道长度的分析研究,确定了源漏工艺条件为磷离子注入能量100keV、剂量5×1015 cm-2。分析了扩散、离子注入源漏掺杂对放大器直流输出的影响,结果表明,当宽长比为4/1时,注入源漏掺杂制作的放大器直流输出与仿真值差异为0.28V,优于扩散工艺。     

硼扩散引起薄SiO2栅介质的性能退化

采用表沟p+多晶硅栅/PMOSFET代替埋沟n+多晶硅栅/PMOSFET具有易于调节阈值电压、降低短沟效应和提高器件开关特性的优点,因而在深亚微米CMOS工艺中被采纳.但是多晶硅掺杂后的高温工艺过程会使硼杂质扩散到薄栅介质和沟道区内,引起阈值电压不稳定和栅介质击穿性能变差.迄今为止对硼扩散退化薄栅介质可靠性的认识并不是很明朗,为此本文考察了硼扩散对薄栅介质击穿电荷和Fowler-Nordheim (FN)电应力产生SiO2/Si界面态的影响.     

Development of the readout system for waveguide multilayer optical card

Waveguide multilayer optical card （WMOC） is a novel storage device of three-dimensional optical information. An advanced readout system fitting for the WMOC is introduced in this paper. The hardware mainly consists of the light source for reading, WMOC, motorized stages addressing unit, microscope imaging unit, CCD detecting unit and PC controlling ＆ processing unit. The movement of the precision motorized stage is controlled by the computer through Visual Basic （VB） language in software. A control panel is also designed to get the layer address and the page address through which the position of the motorized stages can be changed. The WMOC readout system is easy to manage and the readout result is directly displayed on computer monitor.     

Nanoimprint Lithography -A Next Generation High Volume Lithography Technique

IntroductionNanoimprint Lithography is a well-acknowl-edged low cost, high resolution, large area pattern-ing process. It includes the most promising methods,high-pressure hot embossing lithography (HEL) [2],UV-cured imprinting (UV-NIL) [3] and micro contactprinting (m-CP, MCP) [4]. Curing of the imprintedstructures is either done by subsequent UV-lightexposure in the case of UV-NIL or by cooling downbelow the glass transition temperature of the ther-moplastic material in case of HEL…     

Collinear phase-matching study of terahertz-wave generation via difference frequency mixed in GaAs and Inp

The collinearly phase-matching condition of terahertz-wave generation via difference frequency mixed in GaAs and InP is theoretically studied. In collinear phase-matching, the optimum phase-matching wave hands of these two crystals are calculated. The optimum phase-matching wave bands in GaAs and lnP are 0.95-1.38μm and 0.7-0.96μm respectively. The influence of the wavelength choice of the pump wave on the coherent length in THz-wave tuning is also discussed. The influence of the temperature alteration on the phase-matching and the temperature tuning properties in GaAs crystal are calculated and analyzed. It can serve for the following experiments as a theoretical evidence and a reference as well.     

Effects of the alloy compositions on the phonon-polaritons in ternary mixed crystals

Composition dependence of bulk and surface phonon-polaritons in ternary mixed crystals are studied in the framework of the modified random-element-isodisplacement model and the Bom-Huang approximation. The numerical results for Several Ⅱ - Ⅵ and Ⅲ- Ⅴ compound systems are performed, and the polariton frequencies as functions of the compositions for ternary mixed crystals AlxGa1-xAs, GaPxAS1-x, ZnSxSe1-x, GaAsxSb1-x, GaxIn1-xP, and ZnxCd1-xS as examples are given and discussed. The results show that the dependence of the energies of two branches of bulk phonon-polaritons which have phonon-like characteristics, and surface phonon-polaritons on the compositions of ternary mixed crystals are nonlinear and different from those of the corresponding binary systems.     

Influence of PVK ： NPB hole transporting layer on the characteristics of organic light-emitting devices

A doping system consisting of NPB and PVK is employed as a composite hole transporting layer （CHTL）. By adjusting the component ratio of the doping system, a series of devices with different concentration proportion of PVK ： NPB are constracted. The result shows that doping concentration of NPB enhances the competence of hole transporting ability, and modifies the recombination region of charge as well as affects the surface morphology of doped film. Optimum device with a maximum brightness of 7852 cd/m^2 and a power efficiency of 1.75 lm/W has been obtained by choosing a concentration proportion of PVK ： NPB at 1：3.     

New insert layer structure OLEDs

An insert layer structure organic electroluminescent device（OLED） based on a new luminescent material （Zn（salen）） is fabricated. The configuration of the device is ITO/CuPc/NPD/Zn（salen）/Liq/LiF/A1/CuPc/NPD/Zn（salen）/Liq/LiF/A1. Effective insert electrode layers comprising LiF（1nm）/Al（5 nm） are used as a single semitransparent mirror, and bilayer cathode LiF（1 nm）/A1（100 nm） is used as a reflecting mirror. The two mirrors form a Fabry-Perot microcavity and two emissive units. The maximum brightness and luminous efficiency reach 674 cd/m^2 and 2.652 cd/A, respectively, which are 2.1 and 3.7 times higher than the conventional device, respectively. The superior brightness and luminous efficiency over conventional single-unit devices are attributed to microcavity effect.     

Analysis of error performance on Turbo coded FDPIM

Due to variable symbol length of digital pulse interval modulation（DPIM）, it is difficult to analyze the error performances of Turbo coded DPIM. To solve this problem, a fixed-length digital pulse interval modulation（FDPIM） method is provided. The FDPIM modulation structure is introduced. The packet error rates of uncoded FDPIM are analyzed and compared with that of DPIM. Bit error rates of Turbo coded FDPIM are simulated based on three kinds of analytical models under weak turbulence channel. The results show that packet error rate of uncoded FDPIM is inferior to that of uncoded DPIM. However, FDPIM is easy to be implemented and easy to be combined, with Turbo code for soft-decision because of its fixed length. Besides, the introduction of Turbo code in this modulation can decrease the average power about 10 dBm, which means that it can improve the error performance of the system effectively.     

A method for calculating the center position of collimated light

It is a key problem to accurately calculate beam spots＇ center of measuring the warp by using a collimated laser. A new method, named double geometrical center method （DGCM）, is put forward for the first time. In this method, a plane wave perpendicularly irradiates an aperture stop, and a charge couple device （CCD） is employed to receive the diffraction-beam spots, then the geometrical centers of the fast and the second diffraction-beam spots are calculated respectively, and their mean value is regarded as the center of datum beam. In face of such adverse instances as laser intension distributing defectively, part of the image being saturated, this method can still work well. What＇s more, this method can detect whether an unacceptable error exits in the courses of image receiving, processing and calculating. The experimental results indicate the precision of this method is high.     

Resolution Enhancement Technology:Integrated Process Solutions using OPC

DUV lithography, using the 248 nm wavelength, is a viable manufacturing option for devices with features at 130 nm and less. Given the low kl value of the lithography, integrated process development is a necessary method for achieving acceptable process latitude. The application of assist features for rule based OPC requires the simultaneous optimization of the mask, illumination optics and the resist.Described in this paper are the details involved in optimizing each of these aspects for line and space imaging.A reference pitch is first chosen to determine how the optics will be set. The ideal sigma setting is determined by a simple geometrically derived expression. The inner and outer machine settings are determined, in turn,with the simulation of a figure of merit. The maximum value of the response surface of this FOM occurs at the optimal sigma settings. Experimental confirmation of this is shown in the paper.Assist features are used to modify the aerial image of the more isolated images on the mask. The effect that the diffraction of the scattering bars (SBs) has on the image intensity distribution is explained. Rules for determining the size and placement of SBs are also given.Resist is optimized for use with off-axis illumination and assist features. A general explanation of the material' s effect is discussed along with the affect on the through-pitch bias. The paper culminates with the showing of the lithographic results from the fully optimized system.     

Preparation and Characterization of TaN ALD Precursors

High purity organic-tantalum precursors for thin film ALD TaN were synthesized and characterized.Vapor pressure and thermal stability of these precursors were studied.From the vapor pressure analysis,it was found that TBTEMT has a higher vapor pressure than any other published liquid TaN precursor,including TBTDET,TAITMATA,and IPTDET.Thermal stability of the alkyl groups on the precursors was investigated using a 1H NMR technique.The results indicated that the tertbutylimino group is the most stable group on TBTDET and TBTEMT as compared to the dialkylamido groups.Thermal stability of TaN precursors decreased in the following order:TBTDET ＞ PDMAT ＞ TBTEMT.In conclusion,precursor vapor pressure and thermal stability were tuned by making slight variations in the ligand sphere around the metal center.