The Deposition And Sulfur In-Stiu Doping Of Cubic Boron Nitride Thin Films By RF Magnetr Sputtering

Cubic boron nitride (c-BN) is a synthesized wide-band-gapⅢ-Ⅴcompound semiconductor, and has lots of excellent physical and chemical properties. For example, ultrahigh hardness only inferior to diamond, inertness against oxidation at high temperature, uneasy reaction with iron group metal, excellent transmission from infrared to ultraviolet band, as well as the possibility of using as n-and p-type doped semiconductors. Cubic boron nitride (c-BN) film has attracted a nice bit of attention for years because of its application in mechanics, thermotics, optics and electronics. This paper focuses on the preparation, nucleation mechanism of c-BN on the interlayer of nickel, the electrical properties of BN thin film doped with sulfur by in-situ doping method using radio frequency magnetron sputter and the characteristic of h-BN/Si n-p heterojunction.In this paper, the buffer interlayer was first formed by depositing a pure nickel layer on si substrate, and then the boron nitride thin films were deposited by using RF sputter. To study the thickness of nickel interlayer how to influence the formation of cubic phase in the boron nitride thin film, we changed the thickness of nickel interlayer by controlling the sputtering time with the same other conditions. The results showed that the thickness of nickel interlayer is the key factor in the formation of cubic boron nitride. The growth of cubic boron nitride at room temperature can be realized by appropriately selecting the thickness of nickel interlayer. We also drew out when the thickness of nickel interlayer was about 150nm, the content of cubic phase in boron nitride thin films would get up to the highest. On the basis of these results, we also examined the impacts of the substrate temperature, substrate bias and annealing conditions on the formation of the cubic boron nitride thin films. We fixed electric oven and quartz boat in sputtering chamber to in situ dope BN thin films by evaporating S powder. The samples were characterized by FTIR. The I-V characteristics of un-doped BN film, doped BN film and post-annealing doped BN film were measured by Keithley 4200. The results showed that we can control the dose of sulfur doped in h-BN film by controlling the evaporation temperature of sulphur.The resistivity of BN films decreased about 1~4 orders of magnitude by controlling the evaporating temperature of sulfur.The hall-effect measurement results of S-doped h-BN film (the S evaporation temperature is 70℃～80℃) showes the sample is n-type doped,the concentration of carriers reach to 6.2×1015 cm-3 and the mobility of carriers is 84.25 cm2/v·s. On this basis, we also studied that (1) the influence of annealing on BN film doped with different dose of sulfur impurities and (2) the influence of annealing temperature on BN film doped with the same sulfur dose.We also studied the I-V characteristic of p-Si / n-BN doped with different sulfur dose.In addition, the influence of annealing on the boron film is also studied under the existing research condition.Because of the poor sealing property of equipment and the water adhesion to the film etc, the unintentional introduction of oxygen, and the products after annealing is mainly the oxides of boron.