红外探测器金属杜瓦瓶锗窗口低温封接技术

为满足钎焊原理和条件的要求,选用软钎焊封接工艺,对锗窗口进行了金属化处理。对金属化材料与焊料的选择、配制以及钎焊等工艺做了大量的探索与实验,并取得了有用的结果。该工艺技术已应用于制作红外探测器件。     

低本底反康普顿高纯锗γ谱仪

本文介绍的谱仪采用铅-石蜡-铅为主的复合物质屏蔽。HPGe探测器对~(60)Co的1332keV γ射线的相对效率为25％,能量分辨率好于1.75keV。在阱型反符合屏蔽下,系统对放在HPGe端面的~(137)Cs点状薄膜源的峰康比可达800:1;测量时间1000min,置信度95％时,对~(137)Cs点源探测灵敏度好于5.6mBq;谱议在100—2000keV能区内的积分本底好于8.7±0.1次/min,与无反符合屏蔽时相比,压缩倍数为6.6。     

Growth and characterization of germanium and boron doped silicon epitaxial films

The epitaxial growth and characterization of in-situ germanium and boron (Ge/B) doped Si epitaxial films is described. As indicated by secondary ion mass spectroscopy and spreading resistance measurements, the total and electrically activated B concentrations are essentially identical and independent of Ge incorporation. The B and Ge concentrations are uniformly distributed in these Ge/B doped films. A slight enhancement of Hall mobility is obtained, possibly due to the stress relief induced by Ge counterdoping. Carrier conduction in these films is due to the activated B with an activation energy of 0.04 eV as revealed by conductivity versus temperature measurements. Ge atoms appear to be isoelectronic with Si atoms in these films. A slight degradation of minority carrier diffusion length is observed. Electrical characterization of PN diodes on these Ge/B doped films do not reveal any anomaly. SiO₂ on these Ge/B doped films has similar oxide fixed charge density, interface state density and dielectric breakdown strength compared to silicon dioxide on boron doped epitaxial films. Electron injection reveals a different transport mechanism of the SiO₂ grown on these Ge/B doped films.     

锗γ谱仪在放射性污染监测中的应用

本文介绍了由于核污染产生的环境放射性样品的采集和制备方法，还介绍了所使用的微机多道分析系统，然后阐述了γ谱测量技术，给出了对污染样品的核素分析实例。     

一种新型SiGe-OI脊形光波导的模式分析及结构参数优化

The mode of a novel SiGe-OI optical waveguide is analyzed, and its single-mode conditions are derived. The Ge content and structure parameters of SiGe-OI optical waveguides are respectively optimized. Under an operation wavelength of 1300 nm, the structures of SiGe-OI rib optical waveguides are built and analyzed with Optiwave software, and the optical field and transmission losses of the SiGe-OI rib optical waveguides are analyzed. The optimization results show that when the structure parameters H, h, W are respectively 500 nm, 250 nm, 500 nm and the Ge content is 5%, the total power loss of SiGe-OI rib waveguides is 0.3683 dB/cm considering the loss of radiation outside the waveguides and materials, which is less than the traditional value of 0.5 dB/cm. The analytical technique for SiGe-OI optical waveguides and structure parameters computed by this paper are proved to be accurate and computationally efficient compared with the beam propagation method （BPM） and the experimental results.     

表面钝化对Ge MOS电容可靠性的影响

通过NO、N2O对Ge衬底进行表面钝化,然后采用反应磁控共溅射方法制备HfTiN薄膜,并利用湿N2气氛退火,将HfTiN转化为HfTiON高k栅介质.研究了表面钝化对Ge MOS器件性能的影响.实验结果表明,湿NO表面钝化能生长高质量GeOxNy界面层,有效降低MOS电容的栅极漏电流,增强器件的可靠性.     

Study of Ge2Sb2Te5 Film for Nonvolatile Memory Medium

The amorphous Ge2Sb2Te5 film with stoichiometric compositions was deposited by co-sputtering of separate Ge, Sb, and Te targets on SiO2/Si (100) wafer in ultrahigh vacuum magnetron sputtering apparatus. The crystallization behavior of amorphous Ge2Sb2Te5 film was investigated by X-ray diffraction (XRD), atomic force microscopy (AFM) and differential scanning calorimetry (DSC). With an increase of annealing temperature, the amorphous Ge2Sb2Te5 film undergoes a two-step crystallization process that it first crystallizes in face-centered-cubic (fcc) crystal structure and finally fcc structure changes to hexagonal (hex) structure. Activation energy values of 3.636±0.137 and 1.579±0.005 eV correspond to the crystallization and structural transformation processes, respectively. From annealing temperature dependence of the film resistivity, it is determined that the first steep decrease of the resistivity corresponds to crystallization while the second one is primarily caused by structural transformation from     

锗纳米线的性能与应用

重点分析讨论了锗纳米线在电学、光学、光电导等特性及其在场效应晶体管制造方面的研究应用现状与最新进展。综合分析表明,未经处理的锗纳米线表面存在一层氧化物及缺陷,与电极连接时欧姆接触性能较差,在制备锗纳米线器件以前必须对锗纳米线表面进行钝化以便沉积电极;对锗纳米线进行掺杂可以改善Ge纳米线的性能,制造出实用Ge纳米线器件。指出在一根纳米线上生长硅/锗半导体纳米线形成硅/锗半导体界面,直接用单根纳米线制造具有完整功能的电子器件是将来重要的研究方向。     

MBE自组装量子点生长和结构形态研究

综述了对自组装量子点形态和生长过程所做的探讨和研究。介绍了关于量子点成核和形态的热力学理论、量子点生长过程的计算机模拟及Ge/Si(001)和InAs/GaAs(001)量子点生长和形态的实验观察。鉴于InAs/GaAs(001)体系的复杂性,把对InAs量子点的观察和研究分为"微观"和"宏观"两种。微观研究对象包括量子点原子尺度上的结构、量子点表面小晶面的晶体学的精确取向等,这些性质可能受热运动的影响比较大,在一定程度上是随机的,它们代表了量子点生长行为的复杂性;宏观研究的对象是指量子点密度、纳米尺度形态等大量粒子统计意义上的集体行为,这些性质和行为可能更具有实际意义。因此作者认为,目前研究量子点生长和形态更为有效的方法应该是探寻以量子点宏观行为所表征的简单性。重点介绍中科院半导体所半导体材料重点实验室最近所做的对InAs/GaAs(001)量子点生长过程的实验观察。结果表明,在一般生长条件下(富As,500℃,0.1ML/s),InAs量子点成核和生长应该都是连续的,没有经历被普遍认为的不连续(一级)相变。按照作者的观察,把InAs量子点成核看作是连续(二级)相变更为贴切。     

Ge/Si量子阱结构的C-V特性的模拟

采用有限深对称方势阱近似模型求解薛定谔方程得到Ge/Si量子阱中的子能级分布,并基于迭代法数值求解泊松方程模拟计算了量子阱结构样品在不同偏压下的载流子浓度分布和C-V特性.C-V曲线上电容平台的存在是量子阱结构C-V特性的显著特征,它与量子阱结构参数有密切的关系.随着覆盖层厚度的减小,C-V曲线上平台起始点的电容值增加,并且向低电压方向移动直至其消失.随着量子阱中的掺杂浓度提高,阱中的载流子浓度也会相应增加,那就需要更高的外加电压才能耗尽阱中的载流子,因此平台宽度也就随着掺杂浓度的增加而增加.当覆盖层厚度增加时,由于电压的分压作用,使得降在量子阱上的分压相应减少,因此需要更大的外加偏压才能使阱中载流子浓度全部耗尽,这就使平台的宽度增大.同样地,当覆盖层掺杂浓度增加时,覆盖层中更多的载流子转移到阱内,也就需要更高的外加偏压才能使阱中载流子全部耗尽,平台的宽度也就随之增大.