Fabrication And Characterization Of Red Micro-LED

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.