A new structure of In-based ohmic contacts to n-type GaAs

Electrical, structural and reaction characteristics of In-based ohmic contacts to n-GaAs were studied. Attempts were made to form a low-band-gap interfacial phase of InGaAs to reduce the barrier height at the metal/semiconductor junction, thus yielding low-resistance, highly reliable contacts. The contacts were fabricated by e-beam sputtering Ni, NiIn and Ge targets on VPE-grown n(+)-GaAs film (approximate to 1 mu m, 2 x 10(18) cm(-3)) in ultrahigh vacuum as the structure of Ni(200 Angstrom)/NiIn(100 Angstrom)/Ge(40 Angstrom)/n(+)-GaAs/SI-GaAs, followed by rapid thermal annealing at various temperatures (500-900 degrees C). In this structure, a very thin layer of Ge was employed to play the role of heavily doping donors and diffusion limiters between In and the GaAs substrate. Indium was deposited by sputtering NiIn alloy instead of pure In in order to ensure In atoms to be distributed uniformly in the substrate; nickel was chosen to consume the excess indium and form a high-temperature alloy of Ni3In. The lowest specific contact resistivity (rho(c)) of (1.5 +/- 0.5)x 10(-6) cm(2) measured by the Transmission Line Method (TLM) was obtained after annealing at 700 degrees C for 10 s. Auger sputtering depth profile and Transmission Electron Microscopy (TEM) were used to analyze the interfacial microstructure. By correlating the interfacial microstructure to the electronical properties, InxGa1-xAs phases with a large fractional area grown epitaxially on GaAs were found to be essential for reduction of the contact resistance.

半导体激光器相对强度噪声的实验研究

建立了一套半导体激光器噪声测量系统用于生产测量和科学研究,其特点是简易,且兼容性大.用该系统对相关的半导体激光器(不同腔长,镀膜与不镀膜等)进行了测量研究,着重研究了镀膜与不镀膜的条件对激光器噪声特性的影响,发现镀膜后管芯一致性提高、受反馈影响增大.为实际生产提供了改进建议,即需要针对实际应用来精心选择端面镀膜的反射率,前端面镀膜反射率不能太低.

砷化镓晶片表面损伤层分析

于2010-11-23批量导入

InAs自组织生长量子点的电子俘获势垒

成功地用深能级瞬态谱(DLTS)研究了InAs自组织生长的量子点电学性质，获得2.5原子层InAs量子点电子基态能级在GaAs导带底下约0.13eV，该量子点在荷电状态发生变化时伴随有晶格弛豫，对应俘获势垒为0.32eV。