Preparation Technology And Performance Research Of Boron-doped CVD Diamond Films

Diamond is a kind of superhard multi-functional material that collect a variety ofexcellent physical and chemical properties, pure diamond is a good insulator, bydoping can make it become a wide bandgap semiconductors or corrosion resistantconductor, therefore, the diamond induced by doping in electronics、microelectronics、electrochemistry and machinery processing and other fields have broad applicationprospects, boron doped diamond film is one of current hot research topic, it has goddconductivity、stable chemical inertness and good electrochemical properties, etc;Design of diamond film by selective growth has the linear array structure, canimprove resolution in ultraviolet detector performance, etc. To this end, this paper usethe DC-PCVD system for making boron doped diamond film, through SEM、XRD、XPS and Raman test means analysis the growth characteristics of diamond filmsurface morphology、grain orientation、quality characteristics、stress state、theresistivity and the existing state,etc. Preliminarily study the preparation method ofdiamond film pattern.一、The study of the effect of trimethyl borate on diamond surface morphology、grain orientation、quality characteristicsBy SEM figure can be seen, when the boron concentration is low, the grain sizeof diamond is smaller, refine grain size, crystal shape is complete than when it is notdoped, the gap is small, and it main shows （111） crystal plane, when the concentrationis higher, the diamond grain boundaries become blurred, edges and corners have beenetching trace, this is because the high concentration of boron source increase thesecondary nucleation rate of diamond film.By XRD analysis shows that no doped diamond film I₁₁₁/I₂₂₀ratio is less thanthe value of the standard powder3.7, and it main shows （110） crystal plane. With theincrease of boron concentration, the crystal plane peak of （220） and （311） becomesrelativiely weak, when boron flow is2and4sccm, the diamond film I₁₁₁/I₂₂₀ratio are slightly larger than the standard powder3.7, that shows the grain withoutorientation as a whole.Analysis by Raman tests, adding a small amount of boron doped diamond filmthan the peak of non diamond phase to weak, that shows non diamond phase reductafter boron doping,when the boron content is higher, the peak at near1587cm^-1 began to increase,the non diamond phase increased.By diamond characteristic peaks in the Raman spectrum of scatter can calculatedthe stress value, since the characteristic peak of boron diamond to low frequency drift,the calculated stress is positive, it shows that the boron doped diamond exits tensilestress.二、The study of existence state of boron in diamond film and the resistivityBy XPS spectrum analysis, the diamond film C1s spectrum in283.5ev nearbysp²C–C key characteristic peak intensity increased with the increase of boron sourceconcentraion, shows the non diamond phase carbon content on the rise; C1s spectrain284.72ev nearby sp3C–C key characteristic peak intensity reducted with theincrease of boron concentraion of source, it shows that the quality of diamond film inthe fall. B1s spectrum of189.6ev nearby SP2B–C key characteristic peak increasewith the increase of boron time; B1s spectrum of192.2ev nearby B–O keycharacteristic peak increase with the increase of boron time, thus, with the increase ofdiamond film growth time, are also on the increase of boron content, and boron atomscombin with more amorphous carbon and oxygen atoms, which combine withdiamond carbon atoms in the relatively weak.Through the four point probe method analyzed under different concentration ofdiamond film resistivity change. Along with the increase of the boron concentration,the resistivity drops rapidly, but the boron concentration increase to a certainconcentration, the resistivity changes slowly, this experiment low resistivity up to2.5×10^-2·cm.三、Exploration of the growth process of nano powder on the steel substrateinduce diamond filmSelective growth of diamond film is the key technology of diamond growthpatten. This article preliminarily explored the deposition diamond film on the steelbase and the transition layer, the results shows that directly deposit on the steel base was no rules of the morphology of iron carbide, after the coated with a thin layer ofMo nano powder, the grain size of10to15microns,“cauliflower shape” of diamondfilm. On molybdenum sheets coated with a thin layer of Mo nano powder, we get thediamond film crystal clear, intergranular combining closely, grain size is2to6microns. Analyzing the technical difficulties and direction of further.