InGaAs/InP雪崩光电二极管暗电流机理研究

基于InGaAs/InP雪崩光电二极管,讨论吸收层厚度和少子寿命以及倍增层厚度和少子寿命对暗电流的影响。研究表明,吸收层厚度影响热产生复合(shockley-read-hall, SRH)和缺陷辅助隧穿(trap-assisted tunneling, TAT)暗电流大小,而倍增层厚度则对TAT和直接隧穿(band-band tunneling, BBT)暗电流影响较大。少子寿命可以等效为缺陷的影响,因而对与缺陷相关的SRH和TAT暗电流影响较大。对暗电流机理的分析,为研究低暗电流高信噪比的雪崩器件提供良好的理论预测。     

平面型InGaAs红外探测器I-V特性研究

采用闭管扩散方式,利用SiO2及Si3N4扩散掩膜在NIN型InP/In0.53Ga0.47As/InP外延材料上制备了两种不同的平面型InGaAs红外探测器,研究了室温下不同扩散区面积的两种器件的正向I-V特性及反向暗电流密度与器件周长面积比的关系,结果表明,扩散区边缘的钝化是平面型InGaAs探测器的制备过程中非常重要的一环,而且Si3N4薄膜的钝化效果优于SiO2薄膜。室温下和-0.1V偏压下,采用Si3N4扩散掩膜的器件的暗电流密度约为20nA/cm2。     

In0.53Ga0.47As/InP高速光电二极管材料生长及光电性能

利用低压MOCVD技术制备PIN结构的InP基InGaAs外延材料。采用分层吸收渐变电荷倍增(SAGCM)结构,通过两次Zn扩散、多层介质膜淀积、Au/Zn p型欧姆接触、Au/Ge/Ni n型欧姆接触等标准半导体平面工艺,设计制造正入射平面In_(0.53)Ga_(0.47)As/InP雪崩光电二极管器件。该器件采用与InP衬底晶格匹配的In_(0.53)Ga_(0.47)As材料做吸收层,InP材料做倍增层,同时引入InGaAsP梯度层。探测器件光敏面直径50μm,器件测试结果表明该器件光响应特性正常,击穿电压约43 V,在低于击穿电压3 V左右可以得到大约10 A/W的光响应度,在0 V到小于击穿电压1 V的偏压范围内,暗电流只有1 nA左右。光电二极管在8 GHz以下有平坦的增益,适用于5 Gbit/s光通信系统。     

一种低暗电流高响度InGaAs/InP pin光电探测器

分析了InGaAs/InP pin光电探测器暗电流和响应度的影响因素,并对MOCVD外延工艺以及器件结构进行优化,从而提高器件响应度和降低暗电流。采用低压金属有机化学气相沉积设备(LP-MOCVD)成功制备了InGaAs/InP pin光电探测器,得到了高质量的晶体材料,InGaAs吸收层的背景浓度低于4×1014 cm-3。利用扩Zn工艺制作出感光区直径为70μm的平面光电探测器。测量结果显示,在反偏电压为5 V时,暗电流小于0.05 nA,电容约为0.4 pF。此外,在1 310 nm激光的辐照下,器件的响应度可达0.96 A/W以上。     

基于锌扩散的InGaAs/InP平面型红外探测器快速热退火研究

系统研究了快速热退火对锌扩散的In_0.53Ga_0.47As/InP PIN探测器的影响。利用电化学电容电压和二次离子质谱技术分析了退火前后Zn和净受主的浓度分布,结果表明退火过程会影响杂质浓度,但不影响扩散深度。制备了不同退火条件的In_0.53Ga_0.47As/InP PIN探测器。器件测试反映,未退火的探测器在260~300K具有更低的器件电容和更高的激活能。通过暗电流成分拟合对器件暗电流机制进行分析,未退火器件表现出更低的肖克利-里德-霍尔产生复合电流和扩散电流,因而室温下未退火器件具有更高的峰值探测率。为了制备高性能低掺杂吸收层结构的平面型InGaAs探测器,快速热退火是不必要的工艺。     

InGaAs/InP材料的Zn扩散技术

使用MOCVD反应室进行了InGaAs和InP材料上的Zn扩散工艺条件研究.通过控制扩散温度、扩散源浓度和扩散时间三个主要工艺参数,研究了InGaAs/InP材料的扩散系数和扩散规律,获得了优化的扩散条件.试验表明,该扩散工艺符合原子扩散规律,扩散现象可以用填隙-替位模型解释.样品经过快速退火过程,获得了极高的空穴浓度.InP的空穴浓度达到7.7×1018/cm3,而InGaAs材料达到7×1019/cm3.在优化的扩散条件下,Zn扩散的深度和浓度精确可控,材料的均匀性好,工艺重复性好,能够应用于光电探测器或其他器件.     

MBE脱氧条件与InGaAs/InP APD性能的相关性

InP基InGaAs/InP雪崩光电二极管（APD）对近红外光具有高敏感度,使其成为微弱信号和单光子探测的理想光电器件。然而随着先进器件结构越来越复杂,厚度尺寸从量子点到几微米不等,性能越来越受材料中晶格缺陷的影响和工艺条件的制约。采用固态源分子束外延（MBE）技术分别在As和P气氛保护下对InP衬底进行脱氧处理并外延生长晶格匹配的In_0.53Ga_0.47As薄膜和APD结构材料。实验结果表明,As脱氧在MBE材料质量方面比P脱氧具有明显的优势,可获得陡直明锐的异质结界面,降低载流子浓度,提高霍尔迁移率,延长少子寿命,并抑制器件中点缺陷或杂质缺陷引起的暗电流。因此,As脱氧可以有效提高MBE材料的质量,这项工作优化了InP衬底InGaAs/InP外延生长参数和器件制造条件。     

高速InP/InGaAs雪崩光电二极管

采用分层吸收渐变电荷倍增(SAGCM)结构,通过两次扩散、多层介质淀积、AuZn p型欧姆接触、AuGeNi n型欧姆接触等工艺,设计制造了正面入射平面InP/InGaAs雪崩光电二极管,器件利用InGaAs做吸收层,InP做增益层,光敏面直径50 μm;测试结果表明器件有正常的光响应特性,击穿电压32～42 V,在低于击穿电压2 V左右可以得到大约10A/W的光响应度,在0到小于击穿电压1 V的偏压范围内,暗电流只有1 nA左右;器件在2.7 GHz以下有平坦的增益.     

InGaAs/Si雪崩光电二极管

采用Si/InP低温晶片键合技术,设计并制作了InGaAs/Si雪崩光电二极管.器件利用InGaAs做吸收层,Si做增益层,光敏面大小50μm×70μm;测试结果表明器件有正常的光响应特性,击穿电压为41 V,暗电流为99 nA,此时光电流比暗电流高3个数量级.     

Si基HgCdTe变面积光伏探测器的变温特性研究

通过变面积Si基HgCdTe器件变温I-V测试和暗电流特性拟合分析,研究了不同偏压下n-on-p型Si基HgCdTe光伏器件的暗电流成分与Si基HgCdTe材料少子扩散长度和少子寿命随温度的变化规律.在液氮温度下,随着反向偏压的增大器件的表面漏电流在暗电流中所占比重逐渐增加.在零偏压下,当温度低于200 K时材料的少子...     

Optical properties of Zn-diffused InP layers for the planar-type InGaAs/InP photodetectors

Zn diffusion into InP was carried out ex-situ using a new Zn diffusion technique with zinc phosphorus particles placed around InP materials as zinc source in a semi-closed chamber formed by a modified diffusion furnace.The optical characteristics of the Zn-diffused InP layer for the planar-type InGaAs/InP PIN photodetectors grown by molecular beam epitaxy (MBE) has been investigated by photoluminescence (PL) measurements.The temperature-dependent PL spectrum of Zn-diffused InP samples at different diffusion temperatures showed that band-to-acceptor transition dominates the PL emission,which indicates that Zn was commendably diffused into InP layer as the acceptor.High quality Zn-diffused InP layer with typically smooth surface was obtained at 580 ℃ for 10 min.Furthermore,more interstitial Zn atoms were activated to act as acceptors after a rapid annealing process.Based on the above Zn-diffusion technique,a 50μm planar-type InGaAs/InP PIN photodector device was fabricated and exhibited a low dark current of 7.73 pA under a reverse bias potential of-5 V and a high breakdown voltage of larger than 41 V (I ＜ 10 μA).In addition,a high responsivity of 0.81 A/W at 1.31 μm and 0.97 A/W at 1.55 μm was obtained in the developed PIN photodetector.     

平面型InGaAs探测结构中p型杂质的二维扩散行为研究

在平面型InGaAs P-i-N短波红外探测结构中,p型杂质在材料中纵向和横向的扩散是决定pn结位置及其光电性能的主要因素,本文采用扫描电容显微方法(SCM)获得了扩散成结InGaAs/InAlAs像元剖面的二维载流子分布,从而实现对不同扩散条件下pn电场结的精确定位和分析.此外,对于InGaAs/InP探测器,SCM...     

Au掺杂碲镉汞长波探测器技术研究

昆明物理研究所多年来持续开展了对Au掺杂碲镉汞材料、器件结构设计、可重复的工艺开发等研究,突破了Au掺杂碲镉汞材料电学可控掺杂、器件暗电流控制等关键技术,将n-on-p型碲镉汞长波器件品质因子(R₀A)从31.3Ω·cm²提升到了363Ω·cm²(λcutoff=10.5μm@80 K),器件暗电流较本征汞空位n-on-p型器件降低了一个数量级以上。研制的非本征Au掺杂长波探测器经历了超过7年的时间贮存,性能无明显变化,显示了良好的长期稳定性。基于Au掺杂碲镉汞探测器技术,昆明物理研究所实现了256×256 (30μm pitch)、640×512 (25μm pitch)、640×512 (15μm pitch)、1 024×768 (10μm pitch)等规格的长波探测器研制和批量能力,实现了非本征Au掺杂长波碲镉汞器件系列化发展。     

InP/InGaAs(P)材料中的低温开管Zn扩散

为了在InP/InGaAs(P)材料中进行精确的选择扩散,同时又要保证外延生长的多层异质结构不被破坏,提出了一种新的低温开管Zn扩散方法。该法直至在T=500℃,t=5min的条件下,重复性仍很好。应用该法研究了低温条件下Zn在InP,InGaAs(P)材料中的扩散行为。实验首次发现,Zn在InGaAsP材料中的扩散速率与材料中P含量的平方成正比。     

短波红外单光子探测器的发展(特邀)

InP/InGaAs短波红外单光子探测器(SPAD)是目前制备技术较为成熟且获得广泛应用的单光子探测器,通过半导体热电制冷(TEC)即可达到的工作温度(-40℃左右),具有体积小、成本低,方便安装和携带的应用优势;另外,基于常规半导体二极管的芯片制造工艺很容易实现大面阵单光子阵列,除了探测信号,还具备三维数字成像功能。国外包括美国、瑞士、意大利、韩国、日本等对InP/InGaAs SPAD进行了长期持续的研究,目前已研制出单管的货架产品,性能还在不断的优化和改进之中,其单光子探测器阵列呈现了清晰的三维成像效果,正在逐步应用。国内包括重庆光电技术研究所、中国科学院上海技术物理所、西南技术物理研究所、中国科学技术大学、云南大学等对InP/InGaAs SPAD芯片先后进行了器件设计和器件制备研究,目前单管的性能已经达到与国外报道相当的性能。国内单光子探测器阵列的研究获得了一定的进展,但芯片规模和器件性能有待提升。文中对国内外InP/InGaAs短波红外单光子探测器的发展,在设计和研制中存在的问题,以及近10年来的优化改进进行了介绍,重点介绍了高温、高速以及单光子焦平面阵列的发展,并结合新颖...     

Ultra-low dark count InGaAs/InP single photon avalanche diode

A low noise InGaAs/InP single photon avalanche diode (SPAD) is demonstrated. The device is based on planar type separate absorption, grading, charge and multiplication structure. Relying on reasonably designed device structure and low-damage Zn diffusion technology, excellent low-noise performance is achieved. Due to its importance, the physical mechanism of dark count is analyzed through performance characterization at different temperatures. The device can achieve 20% single photon detection efficiency and 320 Hz dark count rate (DCR) with a low after pulsing probability of 0.57% at 233 K.     

Bandwidth enhancement for p-end-illuminated InP/InGaAs/InP p-i-nphotodiodes by utilizing symmetrical doping profiles

This paper shows that the bandwidth of a p-end-illuminated planar InP-InGaAs-InP heterojunction p-i-n photodiode can be promoted by using a rather symmetrical doping profile that is produced through diffusion depth control. Caused by extra-depleted InP region in the end of p-InP, the device with symmetrical doping profile has additional series capacitance and thus has a smaller total capacitance than conventional asymmetrical doping profile. Such devices with 0.3 μm depleted InP cap region, together with 1 μm depleted InGaAs absorption region and 0.3 μm depleted InP buffer region, having the capacitance as small as those devices with 1.6 μm depletion region, while have the carrier transit time as short as those devices with 1.3 μm depletion region. Under appropriate bias condition, which is required for getting rid of the heterointerface effects, the symmetrical device as stated with 40 μm junction diameter can have a 3 dB bandwidth exceeding 17 GHz without inductance optimization. For device with conventional asymmetrical doping profile, that is, the p-n junction locating at ~0.1 μm deep in the InGaAs layer, only a bandwidth of about 15 GHz can be obtained. Due to the same thickness of InGaAs absorption layer, both devices have similar responsivity of ~0.8 A/W at -5 V at 1.3 μm wavelength. However, the heterointerface exposed in the depletion region results in several detrimental effects in symmetrical devices, such as interface-generation current, which leads to slightly increased dark current, and barrier/traps for hole transport, which lead to inferior photoresponse at low biases     

High fmax InP double heterojunction bipolar transistorswith chirped InGaAs/InP superlattice base-collector junction grown byCBE

We report the performance of InP Double Heterojunction Bipolar Transistors (DHBT's) with a chirped InGaAs/InP superlattice B-C junction grown by CBE. The B-C junction of the DHBT was graded with a 10-period InGaAs/InP chirped superlattice (CSL) between the InGaAs base and the lightly doped InP collector. A highly doped thin layer was also included at the end of the CSL to offset the quasi-electric field arising from the grade and suppress further the carrier blocking effect across the B-C heterojunction. The InP/InGaAs CSL DHBT demonstrated a high BV_CEO of 18.3 V with a typical current gain of 55 with minimal carrier blocking up to high current densities. Maximum cutoff frequencies of f_max=146 GHz and f_r=71 GHz were obtained from the fabricated 2×10 μm²-emitter DHBT     

Low-temperature Zn- and Cd-diffusion profiles in InP and formation of guard ring in InP avalanche photodiodes

Zn and Cd diffusion in InP were studied in the wide temperature range of 350-580°C to realize a guard ring in InP avalanche photodiodes (APD's). Hole-concentration profiles for Zn and Cd diffusions at various temperatures were found to be expressed by a unified empirical curve, which decreases exponentially with the distance from the surface, and abruptly decreases at the diffusion front. A graded junction can be formed by diffusion at temperatures lower than 500°C for the n-InP background carrier concentration of 1016cm-3, while an abrupt junction can be formed by higher temperature diffusion. Breakdown voltages for the graded-junction diodes formed by low-temperature diffusion were confirmed to be higher than those for the abrupt-junction diodes formed by the higher temperature diffusion. A guard ring formed by the low-temperature Cd diffusion enabled planar-type InP and InGaAs/InP APD's to have uniform multiplication in the photosensitive area without any edge breakdown.