厚膜型气敏器件膜厚影响气体检测灵敏度的研究

利用化学深沉法制备ＳｎＯ２纳米材料，再利用平面丝网印刷技术制备不同膜厚的ＳｎＯ２厚膜型气敏器件试样，测量不同厚膜气敏器件试样对甲烷气体检测灵敏度和阻温曲线，并进行复阻抗分析。实验表明试样膜厚对检测灵敏度的影响是明显的，试样膜厚在５３μｍ左右对甲烷气体有最大灵敏度。     

一种新型结构的LB膜化学场效应晶体管的气敏特性研究

合成了新型的有机半导体ＬＢ膜气敏材料（ＣＯＴＤＭＡＰＰ），其ＬＢ多层膜拉制在场效应晶体管上，形成了具有ＬＢ－ＯＳＦＥＴ结构的化学场效应晶体管（ＣｈｅｒｎＦＥＴ），该器件置于ＮＯ２，ＮＨ３，ＣＯ和Ｈ２Ｓ等有害气体中，结果表明在ＮＯ２气氛中元件漏电流ＩＤＳ发生变化，并可检测到２ｐｐｍ的ＮＯ２．这种器件的气敏特性在于ＦＥＴ的电流放大作用及ＬＢ膜的有序性的影响．     

SnO_2-Sb薄膜材料的制备及气敏性能

利用等离子体化学气相沉积法制备了ＳｎＯ２－Ｓｂ导电薄膜，测试了ＳｎＯ２－Ｓｂ的气敏效应。结果表明，该薄膜对ＮＯ２气体有较好的气敏特性。当测试温度升高，其气敏响应时间相差无几，但恢复时间变短，同时气敏灵敏度相对提高，当温度达到２００℃以上时，灵敏度基本恒定。同时还可看出，不同阻值的薄膜其气敏灵敏度相差不大。     

气敏器件用SnO_2薄膜材料

采用溶胶－凝胶法以ＳｎＣｌ２·Ｈ２Ｏ和ＺｒＯＣｌ２·８Ｈ２Ｏ为原料,制备出性能优良的纳米ＳｎＯ２薄膜材料。用Ｘ射线衍射仪分析了晶相,ＴＥＭ分析了微观结构。研究了掺杂、处理温度等对其性能的影响。在此基础上制作了ＳｎＯ２薄膜气敏器件,并检测了其气敏特性。     

MOD─SnO＿2气敏材料的TEM、SEM分析

分别用ＴＥＭ、ＳＥＭ分析了ＭＯＤ－ＳｎＯ＿２粉末和薄膜，结果表明，根据热处理条件的不同，晶粒尺寸在几十纳米到微米之间；如果控制旋涂薄膜的厚度小于１００ｎｍ，并进行陡然升温热处理，则簿膜光滑无裂纹；即使得到的ＳｎＯ＿２膜存在微裂纹，但是由于微裂纹形成的颈部尺寸比薄膜厚度大得多，故其气敏特性仍然应当由膜厚决定。     

制造SiO2光波导的新工艺：紫外写入法

本文介绍国外利用ＧｅＯ２掺杂的ＳｉＯ２材料的紫外光敏性制造ＳｉＯ２光波导的研究情况，详细叙述了紫外写入法制造ＳｉＯ２光波导的工艺过程并概述了这种新的工艺优越性。     

键合Si／SiO2／Si结构的C—V特征

本文研究了理想Ｓｉ／ＳｉＯ２／Ｓｉ结构的电容－电压（Ｃ－Ｖ）特性，提出了根据Ｓｉ／ＳｉＯ２／Ｓｉ的Ｃ－Ｖ特征测量ＳｉＯ２厚度、衬底掺杂浓度和固定电荷的方法，并对键合样品进行了实验。     

Si—Si3N4—SiO2钝化工艺及其应用

介绍了ＬＰＣＶＤ法Ｓｉ３Ｎ４膜与ＰＥＣＶＤ法ＳｉＯ２膜的淀积工艺，以及Ｓｉ－Ｓｉ３Ｎ４－ＳｉＯ２钝化工艺在高可靠大电流开关二极管中的应用，并指出了工艺的适用范围。     

SiO_2钝化腹对硅／玻璃静电键合的影响

本文分析了硅／玻璃静电键合过程中硅表面ＳｉＯ２钝化膜的作用．ＳｉＯ２膜的存在使键合过程中的静电力减弱，键合工艺所选择的电压上限受ＳｉＯ２膜击穿电压的控制，对于商用抛光硅片与玻璃，要完成良好的键合，一般ＳｉＯ２厚度要小于０．５μｍ．     

钝化膜抗γ辐照的研究

研究了几种不同的钝化膜的γ辐照特性，初步揭示单纯的ＳｉＯ２膜不具备抗γ辐照的能力，厚度为１００ｎｍ涂有聚酰亚胺的ＳｉＯ２膜当辐照剂量小于１０＾６拉德（Ｓｉ）时具有良好的抗γ辐照作用。同时指出了四甲基氢氧化胺对Ｓｉ－ＳｉＯ２界面也有影响。     

Study of the origin of double peaks in the conductance-voltage plots of Al-SiO2-Si capacitors

It is proved by a series of experiments that the double peaks observed in the conductance-voltage plot of an Al-SiO₂-Si capacitor can be related to the effect of the dangling bonds in the SiO₂-Si interface and the missing oxygen atoms in the oxide. Further, it is shown that one of the peaks can be nearly eliminated by a low-temperature hydrogen anneal. Finally, for resolving the double peaks, the importance of using a 10 kHz test signal is illustrated.     

Resonant inelastic light scattering and photoluminescence in isolated nc-Si/SiO2 quantum dots

Observation at the room temperature the spectra of the resonant inelastic light scattering by the spatially confined optical phonons as well as the excitonic luminescence caused by confinement effects in the ensemble of isolated quantum dots (QDs) nc-Si/SiO₂ is reported. It is shown that the samples investigated are high purity and high crystalline perfection quality nc-Si/SiO₂ QDs without amorphous phase α-Si and contaminants. Comparison between the experimental data obtained and phenomenological model of the strong space confinement of optical phonons revealed the need of the more accurate form of the weighted function for the confinement of optical phonons. It is shown that simultaneous detection of the inelastic light scattering by the confinement of phonons and the excitonic luminescence spectra by the confined electron-hole pairs in the nc-Si/SiO₂ QDs allows selfconsistently to determine more accurate values of the diameter of the nc-Si/SiO₂ QDs.     

Optical and structural properties of thin films precipitated from the sol of silicon nanoparticles

A new technique of growing nanocrytalline silicon (nc-Si) thin films is suggested. The technique involves the centrifuge-assisted size-selective deposition of nanoparticles from a colloidal solution (sol) containing nc-Si powders. The structural and optical parameters of the initial nc-Si powders and films deposited by the newly suggested procedure are studied by transmission electron microscopy and analysis of absorption spectra and Raman spectra. The absorption coefficient of the nc-Si films increases with decreasing dimensions of the constituent nanoparticles. The experimentally measured band gap of the films, E _g, is widened from 1.8 to 2.2. eV on etching the nc-Si powders used for deposition of the corresponding films. On the basis of the analysis of the Raman spectra, it is suggested that the amorphous component is involved in the nc-Si powders and films due to oxygen atoms arranged at the nanoparticle surface.     

Electrical Characteristics of <Emphasis Type="Italic">n</Emphasis>-ZnO/<Emphasis Type="Italic">p</Emphasis>-Si Heterojunction Diodes Grown by Pulsed Laser Deposition at Different Oxygen Pressures

Heterojunction diodes of n-type ZnO/p-type silicon (100) were fabricated by pulsed laser deposition of ZnO films on p-Si substrates in oxygen ambient at different pressures. These heterojunctions were found to be rectifying with a maximum forward-to-reverse current ratio of about 1,000 in the applied voltage range of −5 V to +5 V. The turn-on voltage of the heterojunctions was found to depend on the ambient oxygen pressure during the growth of the ZnO film. The current density–voltage characteristics and the variation of the series resistance of the n-ZnO/p-Si heterojunctions were found to be in line with the Anderson model and Burstein-Moss (BM) shift.     

Etch profile control of high-aspect ratio deep submicrometerα-Si gate etch

The well-acknowledged etch profile drift problem in chip production was investigated with a more accurate meads of measuring actual etch thickness to monitor and correct this drift. Using a high-aspect ratio, 0.1-μm α-Si gate structure, the investigation was specifically focused on the control of transition timing in the critical interval from main etch (ME) to over etch (OE). This required reliable endpoint detection of α-Si which was achieved through the development of a method employing a Kalman-Bucy filter with a real-time spectroscopic ellipsometer (RTSE). The robustness of our endpoint detection technique was tested and demonstrated under the actual physical and chemical disturbance environments of the etching process. Application of this endpoint detection technique to the etch of a 0.1-μm patterned α-Si gate also achieved a significant improvement on the etch profile repeatability     

A Comparison of ZnO Nanowires and Nanorods Grown Using MOCVD and Hydrothermal Processes

A comparison of ZnO nanowires (NWs) and nanorods (NRs) grown using metalorganic chemical vapor deposition (MOCVD) and hydrothermal synthesis, respectively, on p-Si (100), GaN/sapphire, and SiO₂ substrates is reported. Scanning electron microscopy (SEM) images reveal that ZnO NWs grown using MOCVD had diameters varying from 20 nm to 150 nm and approximate lengths ranging from 0.7 μm to 2 μm. The NWs exhibited clean termination/tips in the absence of any secondary nucleation. The NRs grown using the hydrothermal method had diameters varying between 200 nm and 350 nm with approximate lengths between 0.7 μm and 1 μm. However, the NRs grown on p-Si overlapped with each other and showed secondary nucleation. x-Ray diffraction (XRD) of (0002)-oriented ZnO NWs grown on GaN using MOCVD demonstrated a full-width at half-maximum (FWHM) of 0.0498 (θ) compared with 0.052 (θ) for ZnO NRs grown on similar substrates using hydrothermal synthesis, showing better crystal quality. Similar crystal quality was observed for NWs grown on p-Si and SiO₂ substrates. Photoluminescence (PL) of the NWs grown on p-Si and SiO₂ showed a single absorption peak attributed to exciton–exciton recombination. ZnO NWs grown on GaN/sapphire had defects associated with oxygen interstitials and oxygen vacancies.     

Formation of optically active centers in films of erbium-doped amorphous hydrated silicon

We have observed photoluminescence at 1.54 μm from a-Si:H films doped with erbium of various degrees of purity. It is shown that the additional introduction of oxygen activates the Er ions. The effect of silicides and defects in amorphous silicon a-Si:H films and in crystalline silicon c-Si is investigated. Fiz. Tekh. Poluprovodn. 33, 1260–1263 (October 1999)     

Synthesis of thin p-type rutile films

The structure and electrical and optical properties of heterostructures formed on the surface of single-crystal silicon wafers as a result of the heat treatment and pulsed photon treatment of Ti films in oxygen, air, and nitrogen are investigated. It is shown that a TiO₂/Ti₅Si₃/p-Si heterostructure is formed upon heat treatment in air, whereas a TiO₂/TiSi₂/p-Si heterostructure is formed upon photon treatment. It is established that rutile films with pronounced n-type conductivity are formed as a result of the heat treatment of Ni-doped Ti films in oxygen. Rutile films with p-type conductivity are formed upon the thermal annealing of Ti films in air with subsequent photon treatment in nitrogen.     

The influence of erbium on electrical and photoelectric properties of amorphous silicon produced by radio-frequency silane decomposition

Thermal evaporation of tris(2,2,6,6-tetramethyl-2,5-heptadionato) Er(III) inside the plasma gap was used to introduce erbium into amorphous hydrogenated silicon (a-Si:H) obtained by radio-frequency silane decomposition. The samples obtained had a pronounced layered structure due to exhaustion of the erbium source. The layer nearest to the substrate was enriched with erbium, oxygen, and carbon; gave rise to luminescence with a wavelength of 1.535 µm characteristic of ⁴ I _13/2 → ⁴ I _15/2 intra-atomic transitions of erbium; and contained a large number of defects. The top layer contained much fewer defects, was close to undoped a-Si:H in the photoelectric characteristics, and was responsible for photoconductivity in the samples obtained. The experimental data are analyzed in the context of the models for doping of a-Si:H with Er with the resulting emergence of n-type conduction and formation of heterojunction as the film grows.     

氢化非晶硅双极性场效应晶体管

本文着重研究了玻璃栅介质(GGI)氢化非晶硅双极性场效应晶体管(α-Si:HBFET)的转移特性,并比较了SiO_2和SiO_2/α-SiN_x:H栅介质α-Si:HFET的性质.业已发现:(1)硼掺杂和磷掺杂不仅可以人大地提高(GGI)α-Si:HBFET的电流驱动能力,而且可以大大地改善其双极对称性.(2)(GGI)未掺杂α-Si:HBFET可以用来构成静态特性良好的CMOS倒相器.(3)SiO_2栅介质α-Si:HFET具有典型的双极性,但是SiO_2/α-SiN_x:H栅介质α-Si:HFET则不是双极性的.