Study On The Growth Characteristics Of GaN Blue LED

This paper mainly introduces the GaN of GaN-based blue LED specific growth method, introduces various parameters influence on the product properties, and introduces some means of improving product performance:(1), first introduced the GaN basic properties and growth process of the main parameters, epitaxial growth requires comparatively high V/III ratio, V/III ratio will affect material crystal quality, high V/III can decrease the crystal in the screw dislocation and dislocation, improving the crystal quality; high pressure can improve the atomic the surface mobility, high pressure3D is the main mode of growth, low pressure is2D-3D mixed growth pattern, low pressure is also conducive to doping, in Al, In doped usually adopts low pressure.(2), introduced the PSS planar substrate substrate comparison superiority, PSS substrate can effectively reduce the crystal defect measurement, XRD PSS substrate002and102face of half high width is significantly decreased, and the patterned substrate can increase30%light-emitting efficiency; nucleation phase nucleation in thickness to PSS the substrate is a big influence of closed, through experiments we found,4min growth time (20nm-30nm nucleation thickness) can get the best quality of the crystal, armoring layer stage requires higher pressure can inhibit the growth of2D, through the3D model to be more rough surface; growth rate will affect the crystal quality, growth rate is low obtained crystal quality is better, the higher the quality defects and more, growth rate increased from1.64μm/H to3.66μH, X ray diffraction (0002) and GaN (10-12) peakwidth respectively by233arc seconds,263seconds of arc increased to247arc seconds,366seconds of arc, in order to ensure faster and better growth by2μH, generally about um growth rate is most appropriate.(3), introduced the Si as electron sources of major doping method, through the dilute, source and inject MFC to achieve precise control, Si doping and doping concentration is linear; in the nGaN layer and MQW layer by, we graded doping and doping to the current interval extension, can effectively add device electrostatic resistance, can reduce leakage, two kinds of methods can improve the passing rate of ESD is about30%, but the gradient doping may cause the increase of working voltage; among nGaN we use nAlGaN/GaN to control the defect to the upper extension, nAlGaN/GaN superlattice defect can be effectively blocked, but also can achieve certain current expansion, had thicker AlGaN layer due to stress can cause surface appears hexagonal crack.(4), analysis of InGaN quantum well light emitting mechanism of quantum limit is starker effect of electron and hole limit, In phase separation to form rich in In composite; studied during InGaN growth temperature determines the light wavelength, the higher the temperature, the incorporation of In into more difficult, low temperature crystal quality cannot be a very good guarantee, InGaN growth by700-800℃is most suitable, TEGa flow determines the growth rate of quantum trap, trap and barrier thickness increases, the emission wavelength is longer, monochromatic worse,2.5mm-3mm trap width luminous efficiency is highest at the same time the light is better; high pressure is not conducive to the incorporation of In, the pressure the greater incorporation of more difficult, using400mbar pressure growth most appropriate; NH3larger flow, provided by the N protective atmosphere is better, on the incorporation of In has the very big promotion; introduced into InGaN/GaN a trap layer on the optical and electrical properties of MQW,3nm/3nm a well layer to effective stress release, for quantum well effect of the polarization and piezoelectric effect has the great depression, light monochromatic and stability are greatly improved, but too thick to insert layer release effect is not obvious, the trap Cycle excess will introduce defects, reduced device ESD capacity, leakage is obvious.