Fabrication and Simulation of Silicon-on-Insulator Structure with Si3N4 as a Buried Insulator

In order to minimize the self-heating effect of the classic SOI devices,SOI structures with Si3N4 film as a buried insulator (SOSN) are successfully formed using epitaxial layer transfer technology for the first time.The new SOI structures are investigated with high-resolution cross-sectional transmission electron microscopy and spreading resistance profile.Experiment results show that the buried Si3N4 layer is amorphous and the new SOI material has good structural and electrical properties.The output current characteristics and temperature distribution are simulated and compared to those of standard SOI MOSFETs.Furthermore,the channel temperature and negative differential resistance are reduced during high-temperature operation,suggesting that SOSN can effectively mitigate the self-heating penalty.The new SOI device has been verified in two-dimensional device simulation and indicated that the new structures can reduce device self-heating and increase drain current of the SOI MOSFET.     

Finite element analysis of temperature distribution of polycrystalline silicon thin film transistors under self-heating stress

The temperature distribution of typical n-type polycrystalline silicon thin film transistors under self-heating (SH) stress is studied by finite element analysis. From both steady-state and transient thermal simulation, the influence of device power density, substrate material, and channel width on device temperature distribution is analyzed. This study is helpful to understand the mechanism of SH degradation, and to effectively alleviate the SH effect in device operation. __________ Translated from Journal of Semiconductors, 2008, 29(5): 954–959 [译自: 半导体学报]     

PD-SOI NMOSFET负微分电导现象的模拟分析

对无体接触的深亚微米部分耗尽型SOI NMOSFET器件的输出特性分别进行了等温、非等温和非等温能量输运3种模式的模拟,结果表明:SiO2埋层的低导热率使器件在静态工作条件下硅膜温度上升,电子迁移率降低,漏端电流减小;同时,电子温度上升使电子扩散率增加,在无体接触情况下体区电子密度升高,体电势降低,漏端电流减小.通过对模拟结果的分析认为电子迁移率降低和扩散率升高是造成PD-SOI NMOSFET负微分电导现象的主要原因.     

SOI MOSFET自加热效应测试方法

为研究自加热效应对绝缘体上硅(SOI)MOSFET漏电流的影响,开发了一种可同时探测20 ns时瞬态漏源电流-漏源电压(Ids-Vds)特性和80μs时直流静态Ids-Vds特性的超快脉冲I-V测试方法。将被测器件栅漏短接、源体短接后串联接入超快脉冲测试系统,根据示波器在源端采集的电压脉冲的幅值计算漏电流受自加热影响的动态变化过程。选取体硅NMOSFET和SOI NMOSFET进行验证测试,并对被测器件的温度分布进行仿真,证实该方法用于自加热效应的测试是准确有效的,能为建立准确的器件模型提供数据支撑。采用该方法对2μm SOI工艺不同宽长比的NMOSFET进行测试,结果表明栅宽相同的器件,栅长越短,自加热现象越明显。     

Novel oxygen sensor using hot spot on ceramic rod

A novel oxygen sensor using hot spot on ceramic rod of high-T _c superconductor RBa₂Cu₃O_7−δ (R: rare earth element) has been developed. The hot spot appears by the self-heating of the local part on the RBa₂Cu₃O_7−δ ceramic rod when a voltage above threshold is applied at room temperature. This sensor operates without any separate heater by taking advantage of the high temperature of the hot spot wherein oxide ions can diffuse easily. The oxygen concentration is determined from the value of the current flowing through the rod by utilizing the change in the resistivity of the hot spot depending on oxygen partial pressure in atmosphere. Oxygen concentration of 0∼100% can be detected with high sensitivity and the response time is several seconds. The response performance of this oxygen sensor is almost the same as that of limiting-current-type zirconia sensor operating at 500°C.     

蓝宝石衬底上AIGaN／GaN HEMT自热效应研究

建立了包含“自热效应”的AIGaN／GaN HEMT（高电子迁移率晶体管）直流I-V特性解析模型。从理论的角度分析了自热效应对AlGaN／GaN HEMT器件的影响，并同已有的实验结果进行了对比，符合较好。证明基于这种模型的理论分析适于AIGaN／GaN HEMT器件测试及应用的实际情况。     

基于自热型酸化提取铜冶炼渣中有价组分铁

本文以铜冶炼渣为研究对象,采用自热型反应,以加工业硫酸酸化、酸浸提取的方法提取有价元素铁.研究考察了液固比、自热反应温度、溶出时间、溶解温度因素对铜冶炼渣中铁溶出的影响规律,以单因素实验为基础,进行正交实验,优化浸提铜冶炼渣中铁的工艺条件.实验结果表明:铜冶炼渣酸浸提取铁的最优工艺条件为:自热反应温度90℃、液固比0.8、溶出时间30 min、溶解温度70℃,此时铁的提取率达到69.95％,通过XRF(X-ray fluorescence spectrometer,X射线荧光光谱分析仪)、SEM(scanning electron microscope,扫描电子显微镜)、XRD(X-ray diffraction,X射线衍射仪)、EDS(energy dispersive spectroscopy,能谱仪)等手段对浸取渣的物相和微观形貌进行表征,分析结果表明:铜冶炼渣自热酸浸后,浸取渣中只有SiO2、少量含铁化合物以及微量CaSO4存在,说明铜冶炼渣通过自热式酸浸反应可以充分浸取其中的有价组分铁.该法为铜冶炼渣资源化高效利用探索出一条新的工艺思路.     

Influence of organic and inorganic properties of coal-shale on spontaneous combustion liability

Coal and coal-shale undergo low-temperature oxidation when exposed to air, potentially leading to spontaneous combustion. Coal-shale found in association with coal seams vary considerably in their intrinsic properties and spontaneous combustion liability index. Fourteen coal-shale samples collected from four different coal mines in Witbank Coalfield, South Africa, were experimentally investigated. The influence of coal-shale intrinsic properties and spontaneous combustion liability indices (determined by the Wits-Ehac Index and the Wits-CT Index) were established. The liability indices indicate relationships with the intrinsic factors and thus, identifying the major intrinsic factors affecting liability toward spontaneous combustion in these coal-shale samples. The XRF analysis indicated that the coal-shale samples are rich in SiO₂, Al₂O₃ and Fe₂O₃, while the XRD showed that same coal-shale samples are generally dominated with kaolinite and quartz. The coal-shale occurred in association with medium Rank C bituminous coal and contained varying proportion of macerals. The Wits-Ehac Index was unable to reliably determine liability indices of some coal-shale samples, and hence the Wits-CT Index was developed. The results obtained from the characterisation tests may be used as a tool to predict the spontaneous combustion liability in carbonaceous material and may serve as a reference when comparing coal-shale from different coal mines.     

应用于硅基等离子天线的LPIN二极管的自加热效应

介绍了LPIN二极管及其在硅基等离子天线方面的应用,从理论上分析了LPIN二极管自加热效应及其对本征区载流子浓度的影响.仿真分析了不同SOI埋层材料对LPIN二极管本征区载流子浓度的影响.仿真结果显示,LPIN二极管的自加热效应会降低其本征区载流子浓度,通过改变埋层的材料,增加埋层的热导率,可以减弱自加热效应,从而增加本征区载流子浓度,提高硅基等离子天线效率.     

不同水分含量对自热后烤制带鱼品质影响的比较分析

为解决自热鱼类产品杀菌复热后食用品质下降问题,该研究以带鱼为原料,利用测色仪、质构仪、扫描电镜（SEM）以及拉曼光谱,探讨烤制至不同水分含量（70%、60%、50%、40%）、经过灭菌和自热后,比较其色泽、质构和感官品质,确定最佳自热烤制带鱼的水分含量。在140 ℃、160 ℃、180 ℃和200 ℃条件下将带鱼烤制至最佳水分含量,比较其色泽、质构、感官评价、微观结构及蛋白质变性程度,从而得到自热烤制带鱼最佳烤制条件。研究发现,随着水分含量的降低,L*值和白度值分别从64.65和60.74下降至42.23和35.82,a*值和b*分别从-0.59和17.05升高至12.23和24.69。水分含量为40%时带鱼鱼块的硬度、胶着度和咀嚼度分别为水分含量70%的4.27倍、5.53倍和5.89倍。烤制至水分含量为70%时,感官评价的各个单项评分最高。在140 ℃条件下烤制带鱼鱼肉使其含水量至70%时,即烤制温度为140 ℃,烤制时间为24 min 3 s时,鱼肉肌纤维直径较细,肉质较嫩,具有稳定的蛋白质结构,感官品质较佳。该研究成果可为自热鱼类产品品质的提升提供理论依据。