Study Of The Design,Fabrication And Simulation Of Silicon-based Nanocolumn GaN-LED

As a wide band gap semiconductor material,GaN has the characteristics of high thermal conductivity,high temperature resistance,acid and alkali resistance,high hardness,etc.,and can be used to prepare blue,green,and ultraviolet light-emitting devices.GaN-based LED devices have a long lifetime,high reliability,and low energy consumption.They are widely used in full-color displays,general lighting,backlights,medical treatment,and military fields,and are vital to the development of optical communications and the interconnection of everything.For LED devices,the choice of substrate material for epitaxial wafers is very important.Due to its low cost,large size,low resistivity,high thermal conductivity,and complete processing technology,Si has attracted much attention as a substrate material.The growth of the nano-pillar structure effectively releases the stress,effectively suppresses the polarization effect existing in the GaN epitaxial wafer,and can also compensate the stress effect caused by the large difference in thermal expansion coefficient between the silicon substrate and the GaN,which improves the quantum efficiency in the devices.Therefore,the research and application of silicon-based nano-pillar GaN-LEDs have broad prospects.In this paper,the design,fabrication and simulation of silicon-based nano-pillar GaN-LED devices are studied.This paper uses the Atlas module in the Silvaco TCAD simulation software to establish a simulation model of silicon-based nano-pillar GaN-LED and simulate the performance and structural changes of silicon-based nano-pillar GaN-LED.The quantumwell energy band structure,wave function,radiative recombination ratio,carrier concentration,current-voltage characteristic curve,and spectrogram of the nano-pillar LED and planar structure LED with the same experimental structure parameters were simulated and analyzed.Due to the dislocation-free nature of the nanopillar structure,the stress in the quantum well is relieved,the quantum Stark effect is effectively suppressed,the carrier concentration is increased,the threshold is reduced,the spectral intensity is high,and the peak wavelength is blue-shifted.This paper also focuses on the analysis of the numbers of quantumwell,the thickness of the well and barrier layer structures,the in composition content,and the influence of the quantumwell material on the nano-pillar GaN-LED device.The optimal parameters are considered when designing the structure.In summary,a four-period nano-pillar InGaN / GaN multi-quantumwell LED device,the thickness of the InGaN well layer is 3nm,and the thickness of the barrier layer GaN is 10 nm,can obtain better performance.GaN based epitaxial films with GaN buffer layer,Si doped n-GaN layer,InGaN/GaN multilayer quantum well and Mg doped p-GaN layer are grown on silicon substrate by MBE.The array of nanopillars can be observed by scanning electron microscope(SEM).LED chips are fabricated by micro nano machining technology.The obtained nano column epitaxial chips are filled with SOG and etched with FAB.The electrodes are evaporated on the p-GaN layer and Si substrate side.The current voltage characteristics and PL spectral characteristics are measured by applying voltage to the chips.The threshold voltage of nanopillar GaN LED is 1.5V,and the peak wavelength at room temperature is around 410 nm.