Preparation And Electrical Characteristics Of Boron-doped Diamond Film

Diamond films as a superhard material possess many unique performances.Due to their high hardness,high wear resistance,high electron and hole mobility,wideband gap,high optical transmittance,and chemical inertness,they can operate at hostile environments while other materials can't.Pure diamond film is an excellent insulating material with resistivity of more than 1010 ?. cm.Boron-doping,however,can turn it into semiconductor or conductor,or even superconductor under low temperature(about 10K),which extends its applications in electrical fields.In this papper,the author introduced the history and current situation firstly,then made diamond films which were with difffent boron-doped concentrations using HFCVD. The technological of boron-doped diamond films were presented in detail from different aspects such as the choice of boron source,growth parameters,and etc..Experiments show that people can make a better quality diamond film on silicon substrate by HFCVD in this condition: distance between filament and substrate is 6.5mm.Acetone and hydrogen ration of 0.75%,filament power of 6.0KW,1.5Kpa furnace pressure.1. Based on the XRD,it is suggusts that the film is Polycrystalline structure and has very good growth at(111)orientation.2. Based on the SEM, it indicates that the shape of diamond film grain is very clearly, the grain grows well.3. Based on the Raman,the results show that the films with low boron-doping level,sharp diamond characteristic peak at 1332cm-1 can be seen,while characteristic peak of non-diamond phase at 1560cm-1 doesn't present,which indicates that low boron-doping level is favorable to increase the quality of the diamond films.4. Based on the XPS, it suggests that the amount of diamond is much larger than graphite in the sample.But we can't see any boron because its amont is so small in the film.5. We used the Bio-Rad Microscience HL5500 Hall System to measure its electrical property.The results show that its resistivity decreases and carriers concentration increases with the increase of block number of B2O3. When there are 8 blocks B2O3, the resistivity decreases as about 0.11 ?. cmand the carriers concentration is about 1.6×1016cm-1.