基于氧化锌薄膜晶体管的透明指纹识别系统

发布时间：2018-01-28 08:12

本文关键词： 氧化锌薄膜晶体管透明指纹识别有源矩阵传感器　出处：《浙江大学》2017年硕士论文　论文类型：学位论文

【摘要】：当今移动互联网的时代,生物识别技术已是手机必不可少的功能,能与移动智能终端结合的基于硅电容式指纹识别技术已经颇为成熟,而能够在屏幕上运用的透明的指纹识别技术也得到了越来越多的关注。氧化物薄膜晶体管器件由于其透明、工艺步骤少、成本低等特点已在显示领域得到了大规模的应用。显示和指纹识别的矩阵结构颇为相似,利用氧化物薄膜晶体管制作透明指纹识别传感器将有非常广泛的前景。本文首先成功研发一套稳定、可靠的氧化锌薄膜晶体管制备工艺,解决了氧化锌薄膜晶体管稳定性差、可靠性低的问题,再利用氧化锌薄膜晶体管来设计制备透明指纹识别传感器,经过探针台测试,已获得一段与实际相匹配的指纹图像,最后设计了一套能够实时显示的外围检测电路。具体的研究内容和成果如下:1、结合原有工艺步骤深入研究了氧化锌薄膜晶体管的结构特点,针对阈值电压比较负的问题设计了不同的退火条件,并通过大量的尝试,得出不同退火条件将直接影响器件阈值电压的结论,并最终成功制备出阈值电压为正且性能良好稳定的器件以及一套较为成熟的器件制备工艺。2、结合氧化锌薄膜晶体管的器件和有源矩阵结构设计了透明指纹识别传感器充放电结构,用Hspice软件对有源矩阵中的最小单元进行了仿真,经过理论分析,对充放电结构进行优化修改,分别设计了单级放大和双级放大的有源矩阵结构,对这三种不同结构的透明指纹识别传感器进行了仿真对比,提出最优化的传感器电路结构。3、成功制备出基于氧化锌薄膜晶体管的有源矩阵指纹识别阵列,有50×50的大阵列和一些测试小阵列,搭建了一套探针测试平台。通过对不同结构小阵列的测试,检测到电容的充放电信号,计算分析得到了放电信号与感应电容数值之间的对应关系。通过制作指纹模型按压在大阵列上进行模拟真实手指测试,以及对放电信号的处理和整合,获得了一段可靠的指纹图形。4、基于透明指纹识别传感器设计了一套外围检测电路,结合上位机程序对传感器的输出信号进行实时显示。通过对电路和程序的调试,初步完成对电容放电信号以及手指触摸信号的采集。
[Abstract]:In the era of mobile Internet, biometric technology is an indispensable function of mobile phone, and the silicon capacitive fingerprint identification technology which can be combined with mobile intelligent terminal is quite mature. The transparent fingerprint identification technology which can be used on the screen has been paid more and more attention. Because of its transparency, the process steps of oxide thin film transistor devices are less and less. The characteristics of low cost have been widely used in the field of display. The matrix structure of display and fingerprint recognition is quite similar. Making transparent fingerprint identification sensor using oxide thin film transistor will have a very wide prospect. Firstly, a stable and reliable fabrication process of ZnO thin film transistor is successfully developed in this paper. The problem of poor stability and low reliability of ZnO thin film transistor is solved. Then the transparent fingerprint identification sensor is designed and fabricated by using ZnO thin film transistor and tested by probe table. A fingerprint image matching with reality has been obtained, and a set of peripheral detection circuits which can be displayed in real time has been designed. The specific research contents and results are as follows: 1. The structure characteristics of ZnO thin film transistors are deeply studied in combination with the original process steps. Different annealing conditions are designed for the negative threshold voltage problem, and a large number of attempts are made. It is concluded that different annealing conditions will directly affect the threshold voltage of the device. Finally, the device with positive threshold voltage and good stability and a set of mature device fabrication process .2 are successfully fabricated. The charge / discharge structure of transparent fingerprint identification sensor is designed by combining the device and active matrix structure of ZnO thin film transistor. The minimum element in active matrix is simulated by Hspice software. After theoretical analysis, the charge-discharge structure was optimized and the single-stage amplification and two-stage amplification of the active matrix structure were designed, and the three transparent fingerprint identification sensors with different structures were simulated and compared. An optimized sensor circuit structure. 3 is proposed. The active matrix fingerprint identification array based on ZnO thin film transistor is successfully fabricated. There are 50 脳 50 large arrays and some small test arrays. A probe testing platform was built. The charge-discharge signals of capacitors were detected by testing small arrays with different structures. The corresponding relationship between the discharge signal and the inductive capacitance is obtained. The fingerprint model is made to simulate the real finger test on the large array, and the discharge signal is processed and integrated. A reliable fingerprint figure. 4 is obtained, and a peripheral detection circuit based on transparent fingerprint identification sensor is designed. The output signal of the sensor is displayed in real time with the upper computer program. The capacitive discharge signal and the finger touch signal are collected by debugging the circuit and the program.
【学位授予单位】：浙江大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN321.5;TP212;TP391.41

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