Fabrication And Research Of GaN-based Micro-RCLED Based On Si Substrate

Micro-LED(Micro-LED)display device is the thin film,miniaturization and arrayization of traditional LED devices.It is a new display technology composed of semiconductor light-emitting pixel arrays with a size below 50 microns.It has the advantages of high brightness,ultra-high resolution,color saturation,and high luminous efficiency.At the same time,Micro-LED has good stability,long life,and good working temperature.It is not only suitable for flat panel display,but also widely used in many fields such as AR/VR,flexible transparent display,wearable device optoelectronic devices,optical communication,and medical detection.However,size miniaturization also brings about size effects,edge effects,subsequent massive transfers,and difficulty in full-color implementation.This paper proposes a Micro-RCLED that combines ion implantation technology with a resonant cavity(RC,Resonant-Cavity)structure.The ion implantation process is a planar process,which simplifies the process and avoids the side wall damage caused by the traditional etching method;and the resonant cavity structure can make the Micro-LED have greater spontaneous emission intensity,extraction efficiency and better directionality.Spectral purity and temperature reliability.Therefore,this paper studies GaN-based microresonator light-emitting diodes on silicon substrates for device isolation by ion implantation.The main research contents are as follows:1.Design and analysis of the device structure: explain the concept of resonant cavity,microcavity effect and other theoretical knowledge in detail.Discuss the effects of different resonant cavity structures on the luminescence characteristics of the device.The combination of resonant cavity and Micro-LED is realized through processes such as flip chip and wafer bonding.Two resonant cavity structures with different dielectric layer thicknesses and one-quarter central wavelength of the distributed Bragg reflector(DBR)are designed.2.Preparation of devices: GaN-based Micro-RCLEDs on silicon substrates were prepared by photolithography,etching,ion implantation,optical coating and other processes.The resonant cavity structure is a mixed structure of metal and DBR dielectric.In order to better study the influence of the top DBR on the device characteristics,mixed thickness DBRs with different reflectivities(40%,50%,60%)and DBRs with a thickness of a quarter of the optical wavelength were fabricated.At the same time,array devices with sizes of 4 μm,6 μm,8 μm and 10 μm were prepared.3.Device performance test and analysis: The device has been tested in electrical and optical aspects.The results show that the performance of the Micro-RCLED device is improved due to the microcavity effect compared to the Micro-LED without the top DBR.For the DBR device with hybrid structure,the device performance is the best when the top DBR reflectance is 40%,and the spontaneous emission intensity is increased by 3.2 times.Moreover,devices of different sizes have been improved,the spectral half-maximum width has been narrowed by 10 nm,and the spontaneous emission intensity of 10 μm devices has increased by 212.6%.At the same time,the peak wavelength and half-peak width of the device are more stable,and the fluctuation value is less than2 nm;in the DBR device with uniform thickness,the spectral purity is higher,and the half-peak width is about 2 nm narrower than that of the first structure,but at the same time the optical loss increases,the size effect is obvious.In general comparison,the enhancement effect of DBR with mixed thickness is better.The results show that the resonant cavity structure can be well applied to Micro-LED devices.Micro-RCLED devices will have broader application prospects.