MOS-based model of four-transistor CMOS image sensor pixels for photoelectric simulation

By using the MOS-based model established in this paper, the physical process of photoelectron generation, transfer, and storage in the four-transistor active pixel sensor (4T-APS) pixels can be simulated in SPICE environment. The variable capacitance characteristics of double junctions in pinned photodiodes (PPDs) and the threshold voltage difference formed by channel nonuniform doping in transfer gates (TGs) are considered with this model. The charge transfer process of photogenerated electrons from PPDs to the floating diffusion (FD) is analyzed, and the function of nonuniform doping of TGs in suppressing charge injection back to PPDs is represented with the model. The optical and electrical characteristics of all devices in the pixel are effectively combined with the model. Moreover, the charge transfer efficiency and the voltage variation in PPD can be described with the model. Compared with the hybrid simulation in TCAD and the Verilog-A simulation in SPICE, this model has higher simulation efficiency and accuracy, respectively. The effectiveness of the MOS-based model is experimentally verified in a 3 μ m test pixel designed in 0.11 μ m CIS process.     

哈尔滨市平房区碘缺乏病的自我考评结果分析

对哈尔滨市平房区7～10岁学龄儿童尿碘、甲状腺肿及用户碘盐进行调查，其结果为：尿碘中位数为315μg／L，＜50μg／L者占5．7％，＜100μg／L者占10．6％；甲状腺肿大率为21．80％；盐碘中位数为46．4×10-6，＜20×10－6者占3．9％，按照WHO、UNICEF、ICCIDD三个国际组织提供的考核评估标准，尿碘、盐碘水平已达标，但甲状腺肿大率未达标。     

复合漏电模型建立及阶梯场板GaN肖特基势垒二极管设计

准垂直GaN肖特基势垒二极管(SBD)因其低成本和高电流传输能力而备受关注.但其主要问题在于无法很好地估计器件的反向特性,从而影响二极管的设计.本文考虑了GaN材料的缺陷以及多种漏电机制,建立了复合漏电模型,对准垂直Ga N SBD的特性进行了模拟,仿真结果与实验结果吻合.基于此所提模型设计出具有高击穿电压的阶梯型场板结构准垂直GaN SBD.根据漏电流、温度和电场在反向电压下的相关性,分析了漏电机制和器件耐压特性,设计的阶梯型场板结构准垂直GaN SBD的Baliga优值BFOM达到73.81 MW/cm~2.     

应用碘酸盐快速定量方法对1762份高低浓度碘盐的筛查分析

对1762份碘盐进行了快速定量检测筛查,并与实验室方法对照,检测结果为:①销售点碘盐含碘量 M 为40.5×10-6,合格率为97.4%;非碘盐及碘盐含碘量 M＜20×10-6,均为"0";＞60×10-6为2.6%.②居民食盐含碘量 M为 40.0×10-6,合格率为95%;＜20×10-6 为2.5%,＞60×10-6 为0.7%;非碘盐为1.8%.本法与实验室定量方法比较,P＞0.05,无显著差异.判定本法是准确的.     

硫酸铈接触法在碘盐检测中的应用

用硫酸铈接触法对哈尔滨市动力区（１９９２年）和呼兰县（１９９３年）的居民末稍碘盐和碘盐加工点销售点碘盐共２３２份盐样进行了测定分析，其结果：动力区居民末稍盐ｎ＝７６，ｘ±ＳＤ＝１９．５８±１２．８６；碘盐销售点，ｎ＝７７，ｘ±ＳＤ＝２０．５９９±２０．１７４．呼兰县居民末稍盐ｎ＝７５，ｘ±ＳＤ＝８．８９±５．９１；加工点ｎ＝１９，ｘ±ＳＤ＝４６．０８±３８．９３；销售点，ｎ＝４，ｘ±ＳＤ＝２０．７５±１７．７０．平均回收率为９８％．     

Fermi Level Unpinning and Schottky Barrier Modification by Ti, Sc and V Incorporation at NiSi2/Si Interface

A new method is proposed to modify the Schottky barrier height （SBH） for nickel silicide/Si contact. Chemical and electrical properties for NiSi2/Si interface with titanium, scandium and vanadium incorporation are investigated by first-principles calculations. The metal/semiconductor interface states within the gap region are greatly decreased, which is related to the diminutions of junction leakage when Ti-cap is experimentally used in nickel silicide/Si contact process. It leads to an unpinning metal/semiconductor interface. The SBH obeys the Schottky-Mort theory. Compared to Ti substitution, the SBH for electrons is reduced for scandium and increases for vanadium.