【作者】 王艳；

【导师】 刘召军；

【作者基本信息】 哈尔滨工业大学 ， 光学工程， 2020， 硕士

【摘要】 Micro-LED具有高亮度,低功耗,寿命长,高响应速度等优秀特性,现已成为显示领域的热点,Micro-LED全彩显示屏迎来快速发展期,Ga N基蓝光和绿光Micro-LED的制备相对成熟,所以红光Micro-LED制备的研究对未来实现Micro-LED的全彩显示尤为重要。本文对红光Micro-LED从外延片的生长到金属焊盘的制作6步工艺做出详细的介绍,分析进行每一步工艺的原因、工艺的难点及其解决方法。为了进一步了解红光Micro-LED的物理特性,本文对红光Micro-LED进行一系列的表征测试和对比实验,可以分为3个阶段,由浅入深地测试和分析。第一阶段,在蔡司显微镜下观察红光Micro-LED的器件形态,并且测试常温下(300K)的I-V曲线,得到开启电压为1.97V,计算得到理想因子为2.2,推测该器件侧壁存在缺陷,并且测试了光谱曲线,得到中心波长为635nm,半高宽为17nm。第二阶段,分别测试了不同形状的红光Micro-LED的I-V曲线,数据处理得到J-V曲线,发现侧壁面积与发光面积的比值越大,则电流密度越小;测试了圆形和方形红光Micro-LED的光分布,发现方形Micro-LED的光分布比圆形Micro-LED的分布更加均匀,所以在电极的Mask设计时,电极要对称设计,电流和发光才能更加均匀。第三阶段对红光Micro-LED的电学和光学特性的温度依赖性进行研究,随着温度的升高,正向电压降低,电流密度增大,光谱红移,半高宽也在减小。对比同一尺寸下的Al Ga In P基红光Micro-LED和Ga N基蓝光MicroLED的I-V曲线,由于Al Ga In P基红光Micro-LED的边缘效应更加明显,所以红光Micro-LED的正向电流比蓝光Micro-LED的正向电流小两个数量级,因此,在显示领域,红光Micro-LED更难达到显示亮度的要求,但是对比两者的温度灵敏度,发现红光Micro-LED的温度灵敏度(S=2.97m V/K)却是蓝光MicroLED(S=1.43m V/K)和其它二极管温度传感器的两倍,所以红光Micro-LED具有做温度传感器的潜质。未来是一个人工智能时代,5G+VR的结合势必会带动Micro-LED的进一步发展,Micro-LED也将会在更多的领域发挥重要作用。更多还原

【Abstract】 Micro-LED has excellent characteristics such as high brightness,low power consumption,long life and high response speed.It has become a hot spot in the display field.Micro-LED full-color display has ushered in a rapid development period.The preparation of Ga N based blue light and green light Micro-LED is relatively more mature,so the research on the preparation of red Micro-LEDs is particularly important for the realization of full-color display of Micro-LEDs in the future.This thesis introduces a 6-step process from the growth of red Micro-LED epitaxial wafers to the production of metal pads.It gives a detailed introduction to the reasons,difficulties and solutions of each process.In order to further understand the physical characteristics of red Micro-LEDs,this article conducts a series of characterization tests and comparative experiments on red Micro-LEDs,which can be divided into three stages,from shallow to deep testing and analysis.In the first stage,the morphology of the red Micro-LED was observed under a Zeiss microscope,and the I-V curve at normal temperature(300K)was tested.The turn-on voltage was 1.97 V.And the ideal factor was calculated to be 2.2,it was speculated that there were defects in the sidewall of the device.And the spectral curve was tested,and the center wavelength was 635 nm and the FWHM was 17 nm.In the second stage,the I-V and J-V curves of different shapes of red Micro-LEDs were tested separately.The J-V curve was obtained from the data processing.The larger the ratio of the side wall area to the luminous area,the smaller the current density.We tested the light distribution of round and square red Micro-LEDs and found that the light distribution of square Micro-LEDs is more uniform than that of round Micro-LEDs.Therefore,in the process of designing Mask,the more symmetrical the electrode position,the more uniform the current distribution.In the third stage,the temperature dependence of the electrical and optical characteristics of the red Micro-LED is studied.As the temperature increases,the forward voltage decreases,the current density increases,the spectrum is red shifted,and the FWHM decreases.Comparing the I-V curves of Al Ga In P-based red Micro-LED and Ga N-based blue Micro-LED at the same size,because the edge effect of Al Ga In P-based red Micro-LED is more obvious,the forward current of red Micro-LED is two orders of magnitude smaller than that of blue Micro-LED.Therefore,in the display field,it is more difficult for the red Micro-LED to meet the display brightness requirements,but there is a comparison of the temperature sensitivity of the two,and the temperature sensitivity of the red Micro-LED is found(S = 2.97 m V / K)is twice that of blue Micro-LED(S = 1.43 m V / K),so red Micro-LED has the potential to be a temperature sensor.The future is an era of artificial intelligence.The combination of 5G & VR is bound to drive the further development of Micro-LED,which will also play an important role in more fields.更多还原