Study On Growth And Semicoducting Properties Of Cubic Boron Nitride Films By RF Sputter

Cubic boron nitride(cBN) is a synthesized wide-band-gap III-V compound semiconductor and has lots of excellent physical and chemical properties. It has been attracted a nice bit of attention for years because of its application in mechanics, calorifics, optics and electronics. The study of its semicoducting properties is very important for its application in electronics. In this paper we studied the influence of process parameters of depositing cBN films, the n-rype doping of BN films and the properties of p-Si/n-BN heterojunctions and gained the results as follows.1 The influence of process parameters for depositing cBN films was studied allround.cBN films were deposited on Si substrate by radio frequency(RF) Sputtering method. Target material was hexagonal boron nitride (hBN) and working gas was pure argon. Process parameters included RF power, substrate negative bias voltage, substrate temperature and working gas pressure. The influence of process parameters for depositing cBN was studied all round and showed that cBN forms in a very narrow window. Substrate negative bias voltage deeply impacts the nucleation and growth of cBN. There is a threshold value of bias voltage for depositing cBN. cBN forms only if bias voltage exceeds threshold value. Threshold value varies with different parameter windows and is 125V in ours. There is a threshold value of gas pressure too. cBN forms only if pressure under than O.SPa. For the first time, it was found that substrate influences the depositing of cBN.2 For the first time, RF Sputtering method and Vapor doping method have been combined to prepare n type BN films.BN films doped with S are n type conductivity. Undoped BN films exhibit a resistivity of 1.8 X 10" Q cm and those of doped are 7.3 X107 Q cm. The influence of process parameters for doping studied, it showed that both S fountain temperatureand substrate temperature impact the resistivity evidently. Analyzed by XPS and AES, S dopant concentration is made some difference with substrate negative bias voltage.3 The semiconducting properties of p-Si/n-BN heterojunction were studied all round.For the first time, the energy band configuration of p-Si/n-BN heterojunctions were studied and drawn up. The study of the current-voltage (I-V) characteristics showed significant rectifying behavior with reverse saturation current of 3.7 X 10~7A, breakdown voltage of 30V and turn on voltage of 14V. The capacity-voltage (C-V)characteristics are studied too. the dopant concentrate was calculated to 2.75 X1014cm-3.