GaAsP混晶中Te施主深能级的研究

用深能级瞬态谱(DLTS)方法研究了组分范围为x=0.11-0.95的掺Te的GaAs_(1-x)P_(?)混晶中的深能级.结果表明:样品中出现的深能级可分为A,B,C三类,其发射率激活能各约为:E_(?)~A=0.18ev,E_(?)~B=0.28eV,E_(?)~C=0.38eV.其中只有A能级在x=0.23-0.95间的所有样品中出现,B和C能级的出现不存在明显的规律性.进一步研究了A能级的性质后,认为它来源于Te替位杂质的DX中心,而B、C能级的性质可能比较复杂.     

低温下半导体浅能级杂质的陷阱行为

本文研究了低温下半导体浅能级杂质的陷阱行为,计算结果表明:当补偿杂质浓度较高时,浅能级杂质将有明显的陷阱作用,并在10~(17)cm~(-3)时达到最大.在此基础上,本文讨论了浅能级杂质的陷阱行为对双极晶体管截上频率性能的影响.     

SiC中基态施主能级分裂对杂质电离的影响

对SiC中基态施主能级分裂对杂质电离的影响,与温度、掺杂浓度和杂质能级深度的关系进行了系统研究.发现只有在高温且掺杂浓度低的情况下,能级分裂的影响很小可忽略不计,其他条件下均需考虑能级分裂因素.随掺杂浓度的增加,能级分裂的影响增强;随温度的升高,能级分裂影响的整体趋势下降,但存在峰值.当杂质能级深度发生变化时,能级分裂的影响显得比较复杂;曲线上的峰值随着能级深度的增加而向高温方向移动,能级越浅峰就越小;并且在高于某一温度时,随能级的加深能级分裂的影响逐渐增强.     

扫描深能级瞬态谱技术（SDLTS）

深能级瞬态谱(DLTS)技术是研究半导体中深能级杂质与缺陷的有效手段。但是它给出的信息是在一个比较大的范围内的平均值,不能给出微区域深能级的空间分布。而半导体材料的不均匀性往往是受深能级杂质或缺陷的不均匀分布所控制的。所以研究与测量深能级的空间分布以及它们之间的关系,对于提高半导体材料的质量与半导体器件的性能具有十分重要的意义。为此,我们在光注入深能级电流瞬态谱(OTCS)技术的基础上,建立了一种所谓扫描深能级瞬态谱(SDLTS)技术。进行了半绝缘砷化镓中深能级及其空间分布的测量工作。     

计算半导体中杂质能级的分区变分方法

本文从分区变分的概念出发提出了一种计算半导体中杂质能级的新方法.它计入了杂质原于的短程势、长程势和主晶格周期势的贡献,是一种第一原理性的计算方法,便于进行自治计算和考虑缺陷集团的电子态.使用这种方法计算了硅中的浅杂质 P、As、Sb和深杂质S~+、Se~+、Te~+、S、Se、Te的能级.算得的杂质能级变化趋势基本上和实验结果相符.最后讨论了浅杂质和深杂质能级的形成机理和分区变分理论的意义.     

GaN中杂质和缺陷的特性

主要描述了ＧａＮ中施主和受主杂质的能级，氢在掺杂中的作用以及空位的某些特性，同时讨论了该领域未来的研究趋向。     

深能级中心的电场增强载流子产生效应

本文研究了半导体表面空间电荷区中的深能级中心的电场增强载流子产生效应;指出应全面考虑库仑发射和非库仑发射对载流于产生率的影响;给出了相应的产生率计算公式。对计算机计算结果的分析表明,以往的只考虑库仑发射的模型过于简单,本文理论可以较满意地解释有关的实验结果。     

Time—resolved Photoluminescence Spectra of Nominally Disordered GaInP Alloy

Luminescence decay and time-resolved photoluminescence(TRPL) spectra are used for study on the transient luminescence process of the nominally disordered GaInP alloy.The luminescence decay of GaInP alloy shows the temperature and excitation-intensity dependent characters.At 77K and under high excitation intensity, the luminescence decay shows single exponential time dependence, while under low excitation intensity or at 300 K, the luminescence decay shows double exponential time dependence.The analysis indicated that this nominally disordered GaInP alloy actually exhibits a very weak degree of order.The blue-shift of PL peak is observed in the TRPL spectra at 77 K, which is derived from the transfer of the carriers from the ordered domain to the disordered region of the alloy.At 300 K, due to the thermal quenching, the transfer is too weak to be observed.However,The recombination of the carriers between the ordered domain and the disordered region is still devoted to luminesce.     

Deep levels in superlattices

The physics governing deep levels in superlattices and quantum wells is elucidated, with emphasis on the importance of shallow-deep transitions caused by a band edge passing through a deep level, and the accompanying change in doping character of the impurity.     

掺氮区熔硅单晶深能级的研究

DLTS测量发现,在原生掺氮区熔硅单晶中,除E_c-0.20eV、E_c-0.28eV与氮相关外,E_c-0.57eV能级也与氮相关.此三能级在低于400℃、经0.5 小时退火均消失,同时测得三个与氮相关的新能级E_c-0.17eV、E_c-0.37eV和E_c-0.50eV,并研究了它们的退火行为.     

薄膜集成电路合金贴装常见问题分析

随着现代微波混合集成电路向着高性能、高可靠性、小型化、高均一性方向的发展,对合金贴装工艺也提出了越来越高的要求.对合金贴装的要求进行了一些介绍,对合金贴装工艺中的常见问题进行了探讨,分析了其产生的原因,提出了解决的办法.     

Fe和Cu杂质对Si材料响应特性影响的对比分析

针对Si中容易混入Fe杂质和Cu杂质的问题,根据第一性原理和光电响应理论,建立了两种杂质混入下的Si模型,比较了不同间隙位置的杂质原子对Si材料的能级结构及响应特性的影响。结果表明:两种杂质的混入均会导致Si材料能级结构发生变化,从而使Si材料能够出现带外响应,且使得光敏单元的饱和阈值降低。具体而言,Fe杂质在四面体间隙位时,Si材料能级结构会受到明显影响,其带隙减小至0.013 eV,从而在约1 560 nm处出现带外吸收峰。Cu杂质则是在六边形间隙位时对Si材料的影响明显,使材料带隙消失,且在约1 700 nm处出现带外吸收峰。这两种情况下Si 基光敏单元的饱和阈值下降也最为明显,当1 550 nm 激光辐照时,饱和阈值分别为0.001 65 W·cm-2和0.002 54 W·cm-2。分析结果可为光电器件的应用和研制提供参考。     

大功率宽面808nm GaAsP/AlGaAs量子阱激光器分别限制结构设计

本文对有源区条宽100μm的GaAsP/AlGaAs 808nm量子阱激光器分别限制结构进行了理论分析和设计.选取了三种情况的波导层和限制层的铝组分,分别计算和分析了波导层厚度与激光器光限制因子、最大出光功率、垂直发散角和阈值电流密度的函数关系.根据计算结果可知:当波导层和限制层铝组分为0.4和0.5时,采用窄波导结构可以获得器件的最大输出功率为11.2W,发散角为19°,阈值电流密度为266A/cm2;采用宽波导结构可以得到器件的最大输出功率为9.4W,发散角为32°,阈值电流密度为239A/cm2.     

大功率宽面808nm GaAsP/AlGaAs量子阱激光器分别限制结构设计

本文对有源区条宽100μm的GaAsP/AlGaAs 808nm量子阱激光器分别限制结构进行了理论分析和设计.选取了三种情况的波导层和限制层的铝组分,分别计算和分析了波导层厚度与激光器光限制因子、最大出光功率、垂直发散角和阈值电流密度的函数关系.根据计算结果可知:当波导层和限制层铝组分为0.4和0.5时,采用窄波导结构可以获得器件的最大输出功率为11.2W,发散角为19°,阈值电流密度为266A/cm2;采用宽波导结构可以得到器件的最大输出功率为9.4W,发散角为32°,阈值电流密度为239A/cm2.     

An overview of early studies on persistent photoconductivity and other properties of deep levels in GaAsP: The effect of deep levels on light emitting devices

Laser studies carried out at the University of Illinois in 1966 showed that the shortest wavelength at which lasing could be achieved in GaAsP was dependent on then-type dopant. In particular sulfur doping was found to restrict lasing to longer wavelengths. It was suggested that this could be due to the effect of energy levels associated with the higher conduction band minima. This led in 1967 to an investigation of the effect of Te and S donor levels on the properties of GaAsP near the direct-indirect crossover. Samples throughout the composition range were studied using Hall effect measurements from 55 to 400° K and resistivity measurements under hydrostatic pressure between 0 and 7 kbar at 300, 195, and 77° K. The data on Te-doped samples fit the standard energy band models, but S doping was found to exhibit dramatic persistent photoconductivity and other compositional effects similar to the “DX-center” effects later observed in AlGaAs and other materials. This paper summarizes these results on GaAsP:S, and gives a brief overview of other early investigations in compound semiconductors where energy levels associated with higher lying minima were studied and where, in some cases, nonequilibrium effects were observed. A later study on GaAsP:S is also described which shows the effect of S-doping on LED performance. Finally, some of the implications that the existence of deep levels of this type have on light emitting device performance in other alloy systems is discussed.