Preparation And Dielectric Properties Of Aln Thin Films Research

It is a great challenge for us to find one kind of insulating thin filmswith high heat conductivity to solve the "self-heating" problem oftraditional SOI devices.After summarizing the fabrication, the application and the researchingstatus at home and abroad of A1N, high-heat-conductivity A1N thin filmswere deposited by reactive radio frequency magnetic sputtering on N typeSi(100) substrate. The influence of sputtering parameters on depositingrate was studied by Step Surface Profiler; after optimizing the thin filmsfabricating processing, A1N thin films were deposited with greatcomprehensive properties, the breakdown strength of the thin films wereenhanced, the rule of variety of the breakdown strength was discussed intheory, and the varying rule of the relative permittivity was studied andthe reason why it was lower than that of cubic A1N; interface propertywas detected by Positron Annihilation Technology(PAT); As-depositedthin films were annealed by rapid thermal process(RTP) under pure N₂atmosphere, And the effects of annealing on composition & crystalstructure, electrical performance, and interface properties of A1N thinfilms were analyzed.The results show that the depositing rate of reactive sputtering of A1Nthin films is relatively low, it is about 3-8 nm/min. The roughness of thesurface of the films is less than 1 nm, the surface of the thin films isregular, grains equably distribute on the surface with few flaws. Effect oftotal sputtering pressure on composition of the thin films is great, optimalrate of N/A1 is 0.895 from the experiment. Permittivity of A1N thin filmsis 4.4-5.8 with the changing of sputtering power after MIS structure wasformed by depositing A1 onto the A1N thin films. It indicated that thedeposition power and total pressure play important roles on thebreakdown voltage of the thin films whose breakdown voltage is between5 to 13 MV/cm, the greatest breakdown voltage (10.4 MV/cm) was got at250W and 0.3Pa, after annealing the breakdown voltage is enhanced to acertain extent, it attributes to the decrease of unsaturated bonds of A1element. The crystal structure of As-deposited films is amorphous, it then transformed from blende(c-A1N) structure to wurtzite(h-A1N) structure asthe annealing temperature changed from 600 to 1000℃analyzed byXRD. The refractive index becomes greater with the increase of theannealing temperature by a measure of an Elliptical PolarizationInstrument. By PAT, it is indicated that interlayer of the thin film is about20-40 nm and has less flaw after annealed under 1000℃/120s.