Study Of Three-dimensional SiC Diode And Its Key Process

In recent years,silicon as the main material of the electronics industry has reached the physical limits due to its narrow band gap,low thermal conductivity and low critical electric field.SiC,as a third generation semiconductor material,is suitable for high frequency,high temperature,and radiation resistive electronic devices due to its wide band gap,high thermal conductivity,high critical breakdown voltage,high electron velocity saturation and resistance to radiation.In terms of power transmission,due to the inherent properties of SiC,the energy loss is reduced in power conversion process.Compared with traditional semiconductor neutron detectors,SiC neutron detector offer several important advantages,such as high temperature resistance and irradiation.For this reason,SiC neutron detector can be used in the extreme enviroment including nuclear reactors,high energy physical experiment and out space.The trench perforated three dimension SiC neutron detector,which contains high depth to width ratio,can effectively improve the detector efficiency of the detectors.For the designed three-dimensional SiC diode,this thesis introduced the basic process in detail,including dry etching and ion implantation.Due to the stability of SiC materials,wet etching should not be adopted,here dry etching is used to etch trenches and isolation trenches.With respect to diffusion,ion implantation is more suitable for doping of SiC.For p-type doping of SiC,Al is more suitable as a dopant.When ion implantation is performed at a moderate temperature,its resistivity can be reduced.This thesis studied the contact theory of metal and semiconductor and three kinds of measurement methods about specific contact resistance.Reasons about forming ohmic contacts for p-type and n-type SiC materials have also been explained.The process of three-dimensional SiC diodes was studied under the existing process conditions in the laboratory.Lithography,metal vapor deposition,dry etching,ion implantation,and p-type ohmic contact were studied.Among them,the dry etching of SiC was mainly studied.The effects of working pressure,ICP power,RIE power,and gas flow rate on the surface roughness of the etched samples were studied.The relevant process parameters were analyzed and determined,and a set of three-dimensional SiC diode process flow was customized.