首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 105 毫秒
1.
在特定温控下对掺杂气体分子的状态和活性进行控制 ,建立了一套具有自主知识产权的气源分子束外延工艺生长 Si Ge/Si材料的原位掺杂控制技术。采用该技术生长的 Si Ge/Si HBT外延材料 ,可将硼杂质较好地限制在 Si Ge合金基区内 ,并能有效地提高磷烷对 N型掺杂的浓度和外延硅层的生长速率 ,获得了理想 N、P型杂质分布的 Si Ge/Si HBT外延材料  相似文献   

2.
尚林涛  刘铭  邢伟荣  周朋  沈宝玉 《激光与红外》2014,44(10):1115-1118
采用分子束外延的方法进行了低Al组分In1-xAlxSb薄膜的生长和优化。通过在InSb(100)衬底上外延生长一系列不同条件的In1-xAlxSb薄膜,分析总结了衬底的热脱氧特征以及InAlSb薄膜低Al组分(2%左右)的控制,探讨了退火和InSb缓冲层的优化等参数对In1-xAlxSb外延薄膜表面形貌和质量的影响。测试结果表明薄膜质量得到极大改进。  相似文献   

3.
在(111)InSb 和(100)GaAs 衬底上,用分子束外延技术生长了 InSb 和 InAs_xSb_(1-x)外延层。用自动电化学 C—V 法测量了外延层的载流子浓度剖面分布。结果表明:(1)外延层呈 P 型;(2)InSb/GaAs 异质外延层的载流子浓度为(1~2)×10~(16)cm~(-3),比相应的同质外延层 InSb/InSb 的(1~2)×10~(17)cm~(-3)小一个数量级;(3)生长层的载流子浓度剖面分布和质量取决于衬底表面的制备。讨论了有关问题。  相似文献   

4.
分子束外延中的掺硼工艺   总被引:2,自引:0,他引:2  
我们在硅分子束外延中利用共蒸发B_2O_3的方法在硅中进行硼掺杂,掺杂浓度可控制在4×10~(17)cm~(-3)至4.2×10~(19)cm~(-3)之间,这说明不需要利用离子注入或高温掺杂炉,也可以在硅外延层中实现有效的P型硼掺杂.我们还对掺杂外延层的质量进行了初步分析:外延层剖面均匀、没有明显的偏析现象;当硅源速率在 2A/s时,外延层中氧含量与衬底相同.  相似文献   

5.
高编 《红外》2009,30(8):31-31
美国专利US7544532 (2009年6月9日授权)本发明提供采用改进型钝化层的InSb红外光电二极管及传感器列阵,同时还提供了其制作方法。该方法的具体步骤如下:在n型衬底中形成光电二极管探测器区之前,用分子束外延技术在n型InSb衬底上沉积一层AlInSb钝化层;直接通过该AlInSb钝化层注入一种合适的P~+掺杂剂,以形成光电二极管探测器区;有选择地去除AlInSb钝化层,使InSb衬底的第一区暴露出来,然后在InSb衬底第一区形成栅接点;在光电二极管  相似文献   

6.
采用分子束外延方法在GaAs(001)衬底上生长了InSb外延薄膜,其中采用"二步法"制备了不同厚度的低温InSb缓冲层结构.利用Mullins扩散模型对缓冲层的生长过程进行了具体演化.结合扩散模型的计算结果,通过原子力显微镜以及透射电子显微镜研究了InSb缓冲层表面的波纹结构对后续InSb薄膜生长的影响规律.研究表明,适"-3的缓冲层厚度有利于InSb薄膜的外延生长,缓冲层厚度超过60nm后,InSb薄膜表面的粗糙度明显增加,引入了大量位错导致外延薄膜的电性能下降,采用"二步法"生长30-50nm厚的InSb缓冲层比较合适.  相似文献   

7.
张传杰  杨建荣  吴俊  魏彦峰  何力 《激光与红外》2006,36(11):1026-1028,1035
利用自行研制的垂直开管富汞热处理设备,研究了碲镉汞(HgCdTe)富汞热处理技术。经富汞条件下3000C热处理和后续的常规N型热处理,As掺杂的Hg1-xCd,Te分子束外延材料中的As原子已被激活成P型受主,As原子激活率同石英管封管热处理试验的结果基本一致。对包括3in Si基衬底在内的材料退火前后表面形貌进行的比较显示,样品表面形貌可得到很好的保护。研究结果表明,碲镉汞开管富汞热处理技术可用于第三代碲镉汞红外焦平面技术所需大面积多层掺杂异质外延材料的制备。  相似文献   

8.
本文对在InSb及GaAs衬底上用分子束外延生长的InSb分别以Be和Si作p型和n型的掺杂作了研究。当衬底温度超过340℃时,利用二次离子质谱技术,在InSb衬底上生长时,发现Be向表面有反常迁移现象。而在GaAs衬底上生长的掺Be的InSb薄膜中未发现这种迁移。在掺Si的InSb膜中也未发现掺杂剂的再分布现象。InSb中Be的掺杂效率约是GaAs中的一半,若想使Si在InSb中的掺杂效率达到其在GaAs中的掺杂效率,在整个生长过程中,需将衬底温度维持在<340℃。利用低温生长技术,可生长出呈现二维电子气体特性的Si△-掺杂结构。  相似文献   

9.
周朋  刘铭 《红外》2017,38(2):7-10
用原子力显微镜等方法研究了在InSb (001)衬底和(001)偏(111)B面2°衬底上分子束外延生长的同质外延薄膜和掺Al薄膜样品表面的微观形貌。对比了不同衬底同质外延时生长模式的差异,并观察了加入Al后引入的交叉影线,分析了其产生的原因。研究表明,使用有偏角的衬底更有利于减少分子束外延薄膜的表面缺陷。  相似文献   

10.
研究了用分子束外延在(001)取向CdTe衬底上异质外延生长InSb。用双晶x-射线衍射法和俄歇电子光谱法证明在225-275℃的生长温度下InSb单晶层几乎可以互相密合地生长在衬底上而没有界面反应。  相似文献   

11.
Variable magnetic-field Hall and transient photoconductance-lifetime measurements were performed on a series of undoped, In-doped, and As-doped HgCdTe samples grown by molecular beam epitaxy (MBE). Use of quantitative mobility-spectrum analysis (QMSA) combined with multiple carrier-fitting (MCF) techniques indicates that the majority of samples contain an interfacial n-type layer that significantly influences the interpretation of the electrical measurements. This n-type layer completely masks the high-quality electrical properties of undoped or low n-type In-doped HgCdTe, as well as complicating the interpretation of activation in As-doped p-type HgCdTe. Introduction of an intentional n-type background, typically created through doping with In to “recover” high mobility, is actually shown to increase the “bulk” layer conductivity to a level comparable to the interface layer conductivity. Photoconductance-lifetime measurements suggest that In-doping may introduce Shockley-Read-Hall (SRH) recombination centers. Variable-field Hall analysis is shown to be essential for characterizing p-type material. Photoconductance-lifetime measurements suggest that trapping states may be introduced during the incorporation and activation of As. Two distinctly different types of temperature dependencies were observed for the lifetimes of As-doped samples.  相似文献   

12.
The HgCdTe infrared detectors and test structures based on dual or multicolor HgCdTe are desirable for various applications. It is important to control both p-and n-type extrinsic doping in these photovoltaic structures. This paper addresses the issue of activating arsenic as a p-type dopant at temperatures sufficiently low that they will not compromise the integrity of p-n junctions. Midwavelength infrared (MWIR) HgCdTe epilayers were grown by molecular beam epitaxy (MBE) using an In-free type of mounting. The doping was performed by coevaporating arsenic from an elemental solid source during the growth. During postgrowth treatments, we employed a two-step annealing process. During both steps, we used temperatures (300°C, 275°C, and 250°C) that are well below the current standard annealing temperatures. The results suggest that the energy barrier for As transfer from Hg to Te sites can be overcome at 250°C; hence, p doping can be achieved at the temperature of 250°C. The temperature-dependent Hall effect characteristics of the grown samples were measured by the van der Pauw technique with magnetic fields up to 0.4 T.  相似文献   

13.
Precipitation processes in the p-type, n-type, and intrinsic GaAs layers grown by molecular beam epitaxy at a low temperature were studied by transmission electron microscopy. The average spacing, average diameter, and volume fraction of precipitates were measured as a function of the annealing time for the annealing temperature of 700°C. Volume fractions of precipitates are nearly constant in each layer over the period of annealing, implying that the precipitation process has reached the coarsening stage in the annealing times used in the study. The volume fraction of precipitates in the n-type layer is about a half of those in the p-type and intrinsic layers, suggesting that the incorporation rate of excess As into the n-type layer during the growth is lower than those into the p-type and intrinsic layers. Despite a large difference of amounts of excess As in as-grown n-type, p-type, and intrinsic layers, the average spacings and, hence, number densities of precipitates in three layers are nearly identical for each of the annealing conditions.  相似文献   

14.
分子束外延HgCdTe/InSb 材料需要阻止 In 元素在 HgCdTe 中的不受控扩散。我们使用 CdTe缓冲层作为阻挡层,以期控制 In 的扩散。为研究 In 元素在 CdTe 材料中的扩散,我们使用分子束外延方法获得CdTe/InSb样品。考虑到在退火时In 元素可能通过环境扩散污染材料,我们使用 SiO2 作为钝化层,通过对比试验发现 In 元素通过环境扩散污染表面的证据,为控制 In 元素的扩散提供新的思路。  相似文献   

15.
InAs heterojunction bipolar transistors (HBTs) are promising candidates for low power and high frequency (THz) device applications due to their small bandgap, high electron mobility, and high saturation drift velocity. However, doping limits such as the trade-off between desired low intentional n-type concentrations and unintentional doping, and the realization of high p-type concentrations, must still be considered in device design and synthesis. In order to observe the impact of intentional and unintentional n-type doping on diode electrical properties, InAs-based homojunction diodes have been grown on InAs substrates by solid-source molecular beam epitaxy (SSMBE) and were subsequently fabricated and characterized.  相似文献   

16.
Variable magnetic field Hall and transient photoconductance lifetime measurements were performed on a series of undoped, In-doped, and As-doped HgCdTe samples grown by molecular beam epitaxy and metalorganic chemical vapor deposition. Temperature variation and, in the case of Hall, magnetic-field variation are needed to give a more complete picture of the mechanisms that control lifetimes in HgCdTe samples. Recent predictions of recombination lifetimes from full band structure calculations were compared to experimental lifetimes at various doping levels at long-wave infrared (LWIR) and mid-wave infrared (MWIR) compositions. For n-type material, lifetimes from low doping levels fall well below the predictions, implying that Shockley-Read-Hall (SRH) recombination is still dominant. MWIR samples have a lifetime that increases somewhat with carrier concentration, suggesting that In doping passivates the SRH defects for that composition. Lifetimes in p-type MWIR material appear to be well-explained by recent theoretical calculations. In p-type material, trapping states may be introduced during the incorporation and activation of As, since some samples with unusually long lifetimes had a distinctly different type of temperature dependence.  相似文献   

17.
The effect of both n-type and p-type modulation doping on multiple-quantum-well (MQW) laser performances was studied using gas-source molecular beam epitaxy (MBE) with the object of the further improvement of long-wavelength strained MQW lasers. The obtained threshold current density was as low as 250 A/cm2 for 1200-μm-long devices in n-type modulation-doped MQW (MD-MQW) lasers. A very low CW threshold current of 0.9 mA was obtained in 1.3-μm InAsP n-type MD-MQW lasers at room temperature, which is the lowest ever reported for long-wavelength lasers using n-type modulation doping, and the lowest value for lasers grown by all kinds of MBE in the long-wavelength region. Both a reduction of the threshold current and the carrier lifetime in n-type MD MQW lasers caused the reduction of the turn-on delay time by about 30%. The 1.3-μm InAsP strained MQW lasers using n-type modulation doping with very low power consumption and small turn-on delay time are very attractive for laser array applications in high-density parallel optical interconnection systems. On the other hand, the differential gain was confirmed to increase by a factor of 1.34 for p-type MD MQW lasers (NA=5×1018 cm -3) as compared with undoped MQW lasers, and the turn-on delay time was reduced by about 20% as compared with undoped MQW lasers. These results indicate that p-type modulation doping is suitable for high-speed lasers  相似文献   

18.
A thin, highly Si-doped (n-type) interfacial layer is used for controlled barrier lowering in n-type GaAs. The thickness and the doping density of the interfacial n+ layer in the range of 50-100 Å, are extracted from the measured electrical characteristics of Schottky contacts. A model for field-enhanced tunneling current in metal--nGaAs Schottky structures is presented and the experimental results for Al-n+ GaAs devices fabricated using molecular beam epitaxy (MBE) show good agreement.  相似文献   

19.
We have studied the relationship between the arsenic incorporation kinetics and the surface morphology and Si doping behaviour in GaAs(110) films grown by molecular beam epitaxy (MBE). The homoepitaxial growth of GaAs(110) requires low substrate temperatures and high As/Ga flux ratios to obtain films with good surface morphology, and under these conditions Si doped layers exhibit n-type behaviour. At higher growth temperatures and lower As/Ga flux ratios, the epitaxial films are highly faceted and the Si doped layers are p-type. We show that this growth related site switching behaviour and variation in surface morphology is due to a decrease in the As coverage arising from a small and temperature dependent incorporation coefficient of arsenic on this surface.  相似文献   

20.
Metal-organic vapor phase epitaxy (MOVPE) and molecular beam epitaxy (MBE) are the principal techniques for the growth and n-type (Si) and p-type (Mg) doping of III-nitride thin films on sapphire and silicon carbide substrates as well as previously grown GaN films. Lateral and pendeoepitaxy via MOVPE reduce significantly the dislocation density and residual strain in GaN and AlGaN films. However tilt and coalescence boundaries are produced in the laterally growing material. Very high electron mobilities in the nitrides have been realized in radio-frequency plasma-assisted MBE GaN films and in two-dimensional electron gases in the AlGaN/GaN system grown on MOVPE-derived GaN substrates at the crossover from the intermediate growth regime to the droplet regime. State-of-the-art Mg doping profiles and transport properties have been achieved in MBE-derived p-type GaN. The Mg-memory effect, and heterogeneous growth, substrate uniformity, and flux control are significant challenges for MOVPE and MBE, respectively. Photoluminescence (PL) of MOVPE-derived unintentionally doped (UID) heteroepitaxial GaN films show sharp lines near 3.478 eV due to recombination processes associated with the annihilation of free-excitons (FEs) and excitons bound to a neutral shallow donor (D/spl deg/X).  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号