氧化镓薄膜光电导日盲紫外探测器的研制

发布时间：2018-06-13 02:22

  本文选题：β-Ga2O3 + 分子束外延　； 参考：《电子科技大学》2015年硕士论文

【摘要】：近年来,日盲紫外探测技术因其抗干扰能力强、灵敏度高的优点被广泛关注。而基于宽禁带半导体的日盲紫外探测器则因其体积小、寿命长、功耗低等优点,逐步取代真空光电管成为了当前的主流研究方向。相较于Al Ga N、Zn Mg O等常见的日盲紫外敏感材料,β-Ga2O3更容易制备出高质量的薄膜,而且具备较大的禁带宽度,非常适合用于制造日盲紫外探测器。本文利用分子束外延工艺在c面蓝宝石基片上生长β-Ga2O3薄膜,进而研制基于该薄膜的光电导日盲紫外探测器。首先,从材料特性的角度出发,研究了氧化镓薄膜的制备处理方法与日盲紫外探测器主要性能指标的联系。在此基础之上,为实现器件小型化,为后期大面阵的研制打下基础,本论文又从器件结构的角度,研究了器件的缩放特性,并探索了二极管辅助光电导探测器结构。具体研究内容主要分为以下几个部分:(1)论文研究了退火对β-Ga2O3薄膜质量及其制备的光电导日盲紫外探测器性能的影响。本文在800 oC、900 oC、1000 oC、1100 oC四个温度和真空(4.8×10-4Pa)、氧气、氮气三种气氛下对分子束外延生长的β-Ga2O3薄膜进行了退火处理,并利用X射线衍射以及光敏特性测试分别对样品的材料和器件性能进行对比分析,以深入了解退火工艺对β-Ga2O3薄膜质量和光敏特性的影响规律。研究结果显示:随着退火温度的升高,薄膜的(4__02)衍射峰相对强度逐渐降低,探测器的光电流与暗电流均逐渐下降,器件光响应逐渐衰退。氧气退火和氮气退火会影响薄膜中的载流子浓度,从而改变器件的光电流和暗电流。此外,氧气退火还可以减少探测器的下降时间,有效降低持续光电导效应。(2)论文研究了蓝宝石基片原位退火对β-Ga2O3薄膜质量以及光电导日盲紫外探测器性能的影响。为了改善薄膜与基片之间的晶格失配问题,本论文尝试在蓝宝石基片与β-Ga2O3薄膜中引入同质缓冲层,由于缓冲层制备工艺尚不成熟,未能有效改善β-Ga2O3薄膜的质量。但是,研究中发现:在生长β-Ga2O3薄膜之前,先在760oC温度下对蓝宝石基片进行半小时的原位退火处理,可以将薄膜的FWHM从2.0左右降低到1.0左右,有效提高了晶粒取向的一致性,说明基片原位退火处理可明显改善薄膜的生长质量。通过器件制备实验,本论文还发现,氧化镓薄膜的质量越好,光电导探测器的光电流越大,响应度越高,但器件的暗电流也越大,光暗电流比反而会减小,此外,氧化镓薄膜质量对光电导探测器的时间响应特性也有明显影响,薄膜质量越好,光电导探测器的上升时间越短而下降时间越长。(3)论文探讨了了β-Ga2O3薄膜光电导日盲紫外探测器的缩放特性。在保持薄膜生长工艺参数不变的前提下,对光电导日盲紫外探测器的尺寸进行等比例的放大或缩小,通过对各个不同尺寸大小的器件进行性能测试,研究了光电导日盲紫外探测器的器件尺寸对其光电流、暗电流、响应度以及时间响应特性等性能参数的影响。研究结果显示:随着器件尺寸的等比缩小,器件的光电流会有轻微的上升趋势,但整体变化不大。随着尺寸的缩小,器件的响应度会有明显增加,时间响应特性基本不发生变化。因此,叉指电极结构的光电导探测器在经过等比缩小后可以用于大面阵的制作。但叉指电极结构的问题在于,随着器件尺寸的缩小,指条宽度以及指间距会变得非常窄,给器件的加工制造带来了难度。(4)论文探索了二极管辅助光电导日盲紫外探测器。相较于基于叉指电极的器件结构,该新型器件结构在制作工艺上难度更小,而且,通过外接齐纳二极管可以明显增大日盲紫外探测器的光信号与暗信号之间的差值,增强器件的性能,该器件结构的可行性在本工作中已得到初步验证,有希望用于大面阵的研制。
[Abstract]:In recent years, the daily blind ultraviolet detection technology has been widely concerned because of its strong anti-interference ability and high sensitivity. And the daily blind ultraviolet detector based on wide band gap semiconductor has been gradually replacing vacuum phototube because of its small size, long life and low power consumption. It is more common than Al Ga N, Zn Mg O and other common days. The blind UV sensitive material, the beta -Ga2O3 is more easily prepared with high quality thin film, and has a large band gap. It is very suitable for the manufacture of the blind ultraviolet detector. In this paper, we use the molecular beam epitaxy technology to grow the beta -Ga2O3 film on the sapphire base on the C surface, and then develop the optoelectronic blind ultraviolet detector based on this film. On the basis of the study of the relationship between the preparation of gallium oxide film and the main performance index of the daily blind ultraviolet detector, this paper has studied the scaling characteristics of the device and explored the diode on the basis of miniaturization of the device and the foundation for the development of the later large surface array. The main content of the auxiliary photoconductive detector is divided into the following parts: (1) the effects of Annealing on the quality of the beta -Ga2O3 film and the performance of the optoelectronic blind UV detector are studied. This paper is in the three atmosphere of three atmospheres in the atmosphere of four temperatures and four temperatures and vacuum (4.8 * 10-4Pa), 4.8 * 10-4Pa, and 1100 oC. The beta -Ga2O3 thin films grown by beam epitaxy were annealed, and the properties of the materials and devices were analyzed by X ray diffraction and photosensitivity test. The effect of annealing process on the quality and photosensitivity of beta -Ga2O3 films was deeply understood. The results showed that the film was (4__) with the increase of annealing temperature. 02) the relative intensity of the diffraction peak decreases gradually, the photocurrent and the dark current of the detector gradually decrease, and the optical response of the device declines gradually. The oxygen annealing and nitrogen annealing will affect the carrier concentration in the film, thus changing the photocurrent and dark current of the device. In addition, the oxygen annealing can also reduce the drop time of the detector and effectively reduce the duration of the detector. Photoconductivity effect. (2) the effect of the in-situ annealing of sapphire substrate on the quality of beta -Ga2O3 film and the performance of optoelectronic blind UV detector is studied. In order to improve the lattice mismatch between the film and the substrate, this paper attempts to introduce the homogenous buffer layer in the sapphire substrate and the beta -Ga2O3 film, because the preparation process of the buffer layer is not yet available. It is not effective to improve the quality of the beta -Ga2O3 film. However, it is found that before the growth of the beta -Ga2O3 film, a half hour annealing treatment of the sapphire substrate at 760oC temperature can reduce the FWHM from about 2 to about 1, which effectively improves the consistency of grain orientation, indicating the in-situ annealing place of the substrate. It is also found that the better the quality of the gallium oxide film is, the greater the photocurrent of the photoconductive detector is, the higher the response degree is, the larger the dark current and the decrease of the light dark current ratio, in addition, the time response of the gallium oxide film to the photoconductive detector is special. The better the quality of the film, the better the quality of the film, the shorter the rise time of the photoconductive detector and the longer the drop time. (3) the paper discussed the zoom characteristic of the blind UV detector of the photoconductivity of the beta -Ga2O3 film. The effect of the device size on the photocurrent, the dark current, the response degree and the time response characteristic of the optoelectronic blind UV detector is studied by measuring the performance of the devices with different sizes. The results show that the photocurrent of the device will be slight with the size of the device size reduced. As the size decreases, the response degree of the device will increase obviously, and the response characteristic of the time is basically not changed. Therefore, the photoconductive detector of the cross finger electrode structure can be used for the fabrication of large array after the reduction of the equal ratio. But the problem of the structure of the interdigital electrode is that the size of the device is reduced. The width of the finger and the distance between the fingers will become very narrow, and the processing and manufacturing of the devices are difficult. (4) the paper explored the diode assisted optoelectronic blind UV detector. Compared with the device based on the cross finger electrode, the new device structure is less difficult in the fabrication process and can be significantly increased by the external zener diode. The difference between the light signal and the dark signal of the sun blind ultraviolet detector enhances the performance of the device. The feasibility of the device structure has been preliminarily verified in this work, and it is expected to be used for the development of large array.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN23
，

本文编号：2012234