Preparation And Characterization Of Porous GaN Nanomaterials By Electrochemistry

As a representative of the third generation of semiconductors,gallium nitride(GaN)semiconductor materials have shown many advantages such as small specific gravity,prominent specific strength and ideal energy absorption.It has become a hot topic in the global semiconductor research field and attracted the attention of many researchers.At the present stage,dry etching(ICP)is the most commonly used technology in the industrial preparation of porous GaN materials,and its biggest advantage is that it can obtain nano porous structure with well-ordered and generally consistent pore size and appearance due to the orderly mask.However,this technology not only has low selectivity and high cost,but also affects device characteristics due to thermal damage and plasma damage to GaN materials.But electrochemical etching,as one of the representatives of wet etching,can solve these problems.At present,the development of electrochemical etching has become a popular trend.However,at present,the research on this method to prepare porous GaN nanomaterials is still in the experimental stage.Due to the influence of various parameters in electrochemical etching is still not fully understood,the etching situation of the holes is very complex,and especially the influence of electrolyte on the etched holes is less studied,the electrochemical etching mechanism is also being explored.In view of this,this paper takes electrochemically etched porous GaN material as the main line and does the following work:1)Electrochemical etching equipment was assembled.We use Si material instead of GaN material to design experimental parameters,and compare the experimental results with the literature conclusions,so as to verify the feasibility of self-assembly electrochemical etching equipment.2)The influence of etching voltage on the morphology of porous GaN is studied.The etching voltage ranges from 10 V to 25 V,and the average pore size and pore ratio of porous GaN gradually increase and the cell density of porous GaN firstly increase then decrease.Then the band model is used and the experimental results are analyzed theoretically.3)We focus on the influence of electrolyte concentration on the morphology of porous GaN material.The electrolyte is specifically divided into acid,alkali and salt.When the concentration of KOH electrolyte is [20%,50%],the average pore size and pore ratio of porous GaN material first increase and then decrease,and the pore density first decreases and then gradually increases.When the HF electrolyte concentration is [10%,40%],the average pore size and hole rate of porous GaN materials gradually increase,and the pore density presents a gradually decreasing trend.When the concentration of NaCl electrolyte is [10%,20%],the average pore size and pore ratio of GaN samples show a trend of increasing gradually,while the pore density decreases gradually.In addition,the pore distribution of GaN samples is uniform and the shape is regular.In the end,the formula of etching rate was deduced by dynamics model,and the theoretical analysis was carried out by combining the experimental results.Theoretical analysis and experimental results show that when preparing porous GaN materials by electrochemical etching,the control of pore size,pore ratio and pore density can be achieved by changing the etching voltage and electrolyte concentration.