AlInAsSb高倍增低暗电流雪崩光电二极管

	AlInAsSb高倍增低暗电流雪崩光电二极管
	吕粤希
学位类型	硕士
导师	牛智川 ; 徐应强
	2018-05-24
学位授予单位	中国科学院大学
学位授予地点	北京
学位专业	电子与通信工程
关键词	分子束外延 Alinassb 数字合金雪崩光电二极管
其他摘要	雪崩光电二极管（APDs）在成像传感、弱光探测和光纤通信等领域有着广阔的应用价值。其中AlInAsSb四元合金是一种新兴的雪崩倍增材料体系，研究预期其可能拥有比Si更低的k值，同时其工作波长调控灵活性更大、有望实现红外宽谱覆盖的高性能APDs。然而，基于传统生长方法的AlInAsSb体材料性能并没有取得一些理论预言的理想效果，而采用数字合金生长方法的实验结果仍然拥有进一步优化的巨大空间；AlInAsSb作为雪崩倍增材料体系的研究截至目前仅有为数甚少的几篇报道，其基本性能——增益、暗电流等要达到较为理想的水平仍然需要深入研究以获得更多实验样本的支撑。无论是雪崩光电二极管的过剩噪声性能还是增益-带宽积性能，均很大程度上取决于增益、暗电流的大小，我们预期通过合理的设计能有更大提升。本文以高速长距离光纤通信应用所需的1550 nm雪崩光电二极管为器件目标，以实现高倍增、低暗电流为核心问题，深入研究GaSb基AlInAsSb材料生长优化、器件设计建模以及AlInAsSb雪崩光电二极管制备。获得的主要研究成果如下：（1）研究了分子束外延（MBE）Al_0.4In_0.6AsSb、Al_0.7In_0.3AsSb体材料的最佳生长条件，采用HRXRD和STEM测试观察到外延AlInAsSb体材料的偏析所导致的周期性调制现象；（2）采用数字合金生长技术，设计了AlSb、AlAs、AlSb、Sb、In、InAs、In、Sb的快门顺序，并结合表面迁移增强外延（MEE）方法，有效控制了AlInAsSb四元合金的偏析行为，克服了AlInAsSb体材料混溶间隙较大的困难，获得了高质量的AlInAsSb材料；（3）定量地建立了反偏工作下光电器件的电场-电压（EV）、电容-电压（CV）计算模型以及雪崩光电二极管的电流-电压（IV）计算模型，计算得到的结果与测试结果高度吻合；（4）对比了AlInAsSb体材料或数字合金SA(G)CM雪崩光电二极管（GaSb或Al_0.4In_0.6AsSb作吸收区）的性能差异，最终采用AlInAsSb数字合金SAGCM雪崩光电二极管结构方案，获得了高倍增、低暗电流的高性能器件；室温1550 nm的工作波长下初始响应度为0.27 A/W、外量子效率为22%，95%击穿电压下暗电流为14.1 mA/cm²，倍增因子高达~200。 ; Avalanche photodiodes (APDs) has broad application value in imaging and sensing, weak light detection, optical fiber communication, etc. AlInAsSb quaternary is an emerging avalanche multiplication material system and has been expected to have lower k value than Si. At the same time, it has greater freedom to tune working wavelength, showing potential to fabricate infrared broad spectrum high performance APDs. However, traditional AlInAsSb random alloy has not been reported to achieve ideal performance expected, experimental results of digital alloy growth method still have great room for improvement. AlInAsSb quaternary as avalanche multiplication material has only been reported in a few papers, its basic performances such as gain and dark current remain to be discovered deeply in order to get more evidences. Both excess noise and gain-bandwidth performances of APDs depend greatly on gain and dark current, which are expected to improve further through reasonable design. For the application in long haul, high bit rate optical fiber communication, we report deep researches on material growth optimization, device design, modeling and fabrication of GaSb based 1550 nm AlInAsSb high gain, low dark current APDs in this thesis. Main achievements are as follows: (a) Optimal growth conditions of Al_0.4In_0.6AsSb and Al_0.7In_0.3AsSb random alloys grown by molecular beam epitaxy (MBE) were studied, phenomenon of naturally occuring vertical superlattice configuration due to phase segregation was found under HRXRD and STEM. (b) Using digital alloy growth technique, shutter sequence of AlSb, AlAs, AlSb, Sb, In, InAs, In, Sb was designed. Together with migration-enhanced epitaxy method, the large and robust thermodynamic miscibility gap of AlInAsSb random alloy was overcome without phase segregation, showing high quality under different kinds of characterizations. (c) Electric field - voltage (EV), capacitance - voltage (CV) calculation model of reverse biased optoelectronic devices and current - voltage (IV) calculation model of APDs were established, demonstrating high fitting goodness between calculation results and experimental data. (d) Performance differences between AlInAsSb random alloy (with GaSb or Al_0.4In_0.6AsSb random alloy absorption region) and AlInAsSb digital alloy SA(G)CM APDs were compared. High gain, low dark current APDs by using epitaxial structure of AlInAsSb digital alloy SAGCM was obtained eventually. At room temperature and 1550 nm working wavelength, device showed high performance with primitive responsivity of 0.27 A/W, external quantum efficiency of 22%, low dark current of ~14.1 mA/cm² at 95% breakdown and maximum stable gain before breakdown as high as ~200.
学科领域	半导体物理 ; 半导体材料 ; 半导体器件 ; 光电子学
语种	中文
公开日期	2018-06-01
文献类型	学位论文
条目标识符	http://ir.semi.ac.cn/handle/172111/28456
专题	半导体超晶格国家重点实验室
推荐引用方式 GB/T 7714	吕粤希. AlInAsSb高倍增低暗电流雪崩光电二极管[D]. 北京. 中国科学院大学,2018.

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