High B-doped Diamond Film Grown On Al₂O₃ Substrate By Seeding With Diamond Powder

Diamond film possesses numerous physical properties conduciveto its application in high-temperature , high-frequency andhigh-power electronics. The properties include wide band gap, highbreakdown fields, high carrier velocities, and high thermalconductivity .The potential application of the thin diamond film invarious fields has surprisingly increased in recent years. Diamondfilm grown on all kinds of substrates is very important which cansatisfy the need of different fields. In this thesis, high B-dopeddiamond film was quickly deposited respectively on Al₂O3 and SiO₂substrates via hot-filament chemical vapour deposition and theeffects of B-concentration on diamond growth properties wasdiscussed.1) The growth properties and deposition parameters of diamondfilm on Al₂O₃ and SiO₂ substrates by seeding with the diamondpowder of 5nm average size are studied.Diamond film quality rests with deposition parameters whichchiefly include the temperature of the substrate, CH4 concentrationand the distance between hot-filament and the substrate. Theparameters were discussed respectively through the SEM photo,the Raman shift and XRD of diamond films which was depositedby only varying one parameter.In this thesis, by the systemic technology experiment, theoptimized technology parameters are given and the high qualitydiamond film was deposited quickly on Al2O3 and SiO2 substrateby seeding with the diamond powder of 5nm average sizesuccessfully.2) High B-doped diamond film was deposited on Al2O3substrates successfully by seeding with the diamond powder of5nm average size and the effects of B-concentration on diamondfilm deposited have been studied.Firstly 2μ-diamond film is deposited before B-doped diamondfilm is grown. The dopant is solid B powder which locates in around groove on the sample holder. The B concentration indiamond film deposition environment is changed by adding Bpowder in groove.The effects of B-concentration on diamond film quality havebeen studied. It is found that the doped diamond film quality with0.5mg on groove is better than non-doped diamond film. But thedoped diamond film quality falls with increasing of B-powderthrough Raman spectroscopy. It is too found that the Ramanspectroscopy increases at 500cm-1 and 1200cm-1 withB-concentration increasing, which is the characteristic of highdoped diamond film. The resistance of doped-diamond filmdeclines with temperature increasing. The doped diamond film'scrystal is smaller than non-doped diamond film.Crystal-orientation of non-doped diamond film is mainly (220)through the XRD studied. But Crystal-orientation of dopeddiamond film varies from (220) to (111) with B-powder increasing.