延伸波长In0.82Ga0.18As 红外探测器器件结构优化设计

	延伸波长In0.82Ga0.18As 红外探测器器件结构优化设计
	赵旭
学位类型	硕士
导师	缪国庆
	2014-11
学位授予单位	中国科学院大学
学位专业	凝聚态物理
关键词	“铟镓砷” “暗电流” “apsys”
摘要	工作在1-3μm的近红外探测器件，在空间遥感、大气监测、资源勘探等领域都具有重要的应用价值和前景。由于InGaAs材料可以覆盖1-3um近红外波段，具有高吸收系数、高迁移率，高工作温度下高探测率，良好的均匀性和稳定性，优秀的空间抗辐照性能等优点，因此InGaAs探测器是近年来最具发展前景的近红外探测器之一。InGaAs探测器波长可调节，灵敏度较高，但随着空间遥感等军事领域需求的不断提高，要求InGaAs红外探测器应具有更小的暗电流。由于PIN结构红外探测器制作工艺简单、响应度高，目前在设计器件时一般都采用该结构。在器件实际制作之前，对其结构和性能进行模拟、优化，能大大节约资源，提高效率。针对通信用的In0.53Ga0.47As探测器和APD结构InGaAs红外探测器，已经有了大量的研究工作的报道，一种模拟的方法是使用SPICE电路模型模拟器。对材料、结构不同的光电探测器建立对应的电路模型。研究其光电特性。另外一种就是基于载流子连续性方程和泊松方程建立器件模型，利用数值计算工具进行器件特性的分析。综上所述，利用模拟计算的方法优化延伸波长InGaAs探测器的器件结构，从而有效降低暗电流、提高器件光电性能是一项非常有意义的工作。本文采用Crossright公司设计的APSYS对InGaAs红外探测器进行模拟计算，APSYS是一款2D/3D有限元分析软件，它包括了许多物理模型，例如热载流子输运，异质结模型，热分析，拥有强大的模拟功能。这里我们的模型是基于漂移-扩散模型，通过求解自洽解泊松方程、电流连续性方程来得到较为精确的模拟曲线。从而对器件进行优化及设计。本文在验证了APSYS可靠性的基础上，开展了高性能延伸波长InGaAs近红外探测器的研究工作。为了得到暗电流更小的InGaAs红外探测器，本文对探测器材料体系、入光方式的选择进行了计算和讨论，并设计了新型复合盖层InGaAs红外探测器-即PNN盖层InGaAs探测器。得到了以下结论： 1. 研究结果表明器件中各层结构对器件的光电性能都有显著影响。InAlAs相对于InP和InAsP更适合作盖层材料。此外，相比InP衬底，以GaAs为衬底的器件具有更加优良的光电特性。InP衬底器件适合背面入光，而GaAs衬底器件适合正面入光。吸收层厚度增加会导致暗电流、光电流增大，吸收层厚度在2um到3um时器件具有最佳光电性能。同时，可以通过改变缓冲层材料结构对器件的能带进行有效调控。背面入光下，缓冲层和衬底厚度对器件光电特性有显著影响，而缓冲层存在最佳载流子浓度，但改变衬底载流子浓度无影响。 2. 为了满足空间探测等领域的需要——降低暗电流，设计了In0.82Ga0.18As红外探测器的新型结构，优化了复合盖层材料体系、厚度、载流子浓度。计算结果表明，InAlAs/InAsP/InGaAs PNN复合盖层PIN结构InGaAs红外探测器在0.1V偏压下，暗电流值为4E-6A；InAlAs/InAsP/InAlAs PNN复合盖层PIN结构InGaAs红外探测器在0.1V的偏压下，暗电流的值为2E-6A。设计的新型复合盖层InGaAs红外探测器与常规PIN结构InGaAs红外探测器相比，暗电流均小1个数量级。 3. InAlAs/InAsP/InGaAs PNN复合盖层PIN结构InGaAs红外探测器在低于280K的环境中工作时，暗电流主要为缺陷隧穿电流；工作温度在280-300K时，暗电流主要为带间隧穿电流；工作温度大于300K时，暗电流为产生-复合电流和扩散电流。 InAlAs/InAsP/InAlAs PNN复合盖层PIN结构InGaAs红外探测器在低于260K的环境中工作时，暗电流主要为缺陷隧穿电流；工作温度在260k到290K时，暗电流主要为带间隧穿电流；工作温度在290K到320K之间时，暗电流主要为产生-复合电流和扩散电流。
其他摘要	The near-infrared detectors with 1-3 um spectra have wide applications in space remote sensing, atmospheric monitoring, resource exploration and others. Recently, the InGaAs near-infrared detectors emerge as the most promising, as InGaAs can cover 1-3 um spectra and has many advantages such as high absorption coefficient, high mobility, good uniformity and stability, high detection rate in high temperature and excellent resistance to space radiation. However, the generated high dark current restrict its application in remote sensing and military. The infrared detectors with PIN structure are commonly used in device design due to the manufacture simplicity and high responsivity. The simulation and optimization of the device`s structure and function are cost and time effective. In communication, a number of studies have been performed on In0.53Ga0.47As detector and InGaAs infrared detector with APD structure. One simulation is to establish the circuit model using the SPICE to study the photoelectric properties of photo detectors with different materials and structures. Another method is to use numerical tools to analyze device characteristics based on the carrier continuity equation and Poisson's equation. In summary, there is considerable significance to optimize the structures of extended wavelength InGaAs detector by simulation in order to decrease the dark current and improve the device performance. APSYS was adopted to simulate InGaAs infrared detector. APSYS is a 2D/3D finite element analysis software, which contains several powerful simulation models, such as hot carrier transport, heterojunction and thermal analysis model. Our simulation is based on the drift - diffusion model, with solving the Poisson equation and current continuity equation by the self-consistent solution method. Then, a more accurate simulation would be obtained to design and optimize devices. After verifying the reliability of APSYS, the simulation of extended wavelength InGaAs detector was conducted. The material and light illumination were calculated and analyzed. Moreover, a new composite cap InGaAs infrared detector (i.e. PNN cap InGaAs detector) was designed. The conclusions are the followings: The results showed that each layer can affect the photoelectric performance. An improved photoelectric performance was observed in the device with GaAs substrate compared with InP. The back illumination was suitable for device with InP substrate and the front illumination was suitable for the device with GaAs substrate. The increase in the thickness of absorption layer resulted in a up-regulation of dark current and photo current. The optimal thickness was measured as 2 um - 3 um. In addition, the energy band of the device can be regulated by the material structure of buffer layer. In back illuminated detectors, the thickness of substrate and buffer layers had significant impact on the device photoelectric performance. The carrier concentration in buffer layer played a role in device performance and needed to be optimized while the carrier concentration in substrate had no effect on device performance. To meet the needs in space exploration, In0.82Ga0.18As near-infrared detector with new structure was developed to reduce dark current, with optimized cap layers using combined materials, thickness and carrier concentration. The results indicated that the dark current for were 4E-6A and 2E-6A under bias voltage between 0.1 V, for PIN structure InGaAs near-infrared detector with InAlAs/InAsP/InGaAs PNN cap layer and InAlAs/InAsP/InAlAs PNN cap layer, respectively. Such values were smaller by one order of magnitude than that in common PIN structure InGaAs detector. When the working temperature was lower than 280K, the dark current of InGaAs detector with InAlAs/InAsP/InGaAs PNN cap layer was mainly defect tunneling current. The dark current was mainly inter-band tunneling current with working temperature between 280 and 300K and the current was generation - recombination current and the diffusion current with working temperature higher than 300K. Similarly, the dark current of InGaAs detector with InAlAs/InAsP/InAlAs PNN cap layer was mainly defect tunneling current when the working temperature was lower than 260K, inter-band tunneling current with working temperature between 260 and 290K and generation - recombination current and the diffusion current with working temperature between 290 and 320K.
语种	中文
文献类型	学位论文
条目标识符	http://ir.ciomp.ac.cn/handle/181722/44723
专题	中科院长春光机所知识产出
推荐引用方式 GB/T 7714	赵旭. 延伸波长In0.82Ga0.18As 红外探测器器件结构优化设计[D]. 中国科学院大学,2014.

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