Preparation And Properties Of C/Si Doped H-BN Films

As a graphene-like structure III-V semiconductor material,hexagonal boron nitride?h-BN?has many good physical and chemical properties.After selective doping,h-BN will have excellent properties such as conductive,piezoelectric and other semiconductor characteristics.It has become a hot research topic in rencent years.In this paper,intermediate frequency bipolar?IFBP?and radio frequency?RF?magnetron sputtering were used to prepare carbon doped boron nitride?h-BN:C?and silicon doped boron nitride?h-BN:Si?films on single crystal silicon substrates.The films were taken post-annealing when after deposited.The morphology,atomic composition and electrical properties of the films were studied.Research indicates:The dense and continuous h-BN:C films were deposited on a Si substrate successfully by both IFBP and RF sputtering methods,with a resistivity as low as2.9×10⁴-2.5×10⁵?·cm.All the deposited h-BN:C films are composed of fine particles and has an amorphous state with poor crystallinity.After annealing,it was found that the h-BN:C films prepared by IFBP magnetron sputtering formed a granular structure with a main crystal orientation of?101?.At the same time,this method has a faster deposition rate and the prepared films structure is more stable;After annealing at 700°C,the h-BN:C films prepared by RF magnetron sputtering formed an obvious layered structure with the main crystal orientation of?200?.XPS and Raman results indicate that chemical bonds such as?B-?C-N,B-C,N-C have been formed in the films,which proves that C has been successfully doped into h-BN to form a new six-membered ring structure.As the annealing temperature increases from 600°C to 1000°C,the crystallinity and surface roughness of the films first increase and then decrease.In addition,the incorporation of a certain amount of H₂ in the sputtering atmosphere is helpful for improving the stability of the h-BN:C films.The low temperature annealing treatment after deposition can improve the crystallinity and stability.In the preparing h-BN:Si films,Raman results show that the films exhibit significant Raman only at 1366 cm^-1 after Si doping,indicating that the film mainly maintains h-BN structure growth.The same as h-BN:C films,the h-BN:Si films prepared by IFBP has high crystallinity and stable structure,the grain mainly grows in the form of particles;The h-BN:Si films prepared by RF magnetron sputtering were grown in a layer by layer mode.The defects which generated during the deposition process such as dangling bonds and oxygen impurities can be eliminated by Annealing,thereby further enhancing the films stability.The films annealed at 700°C has narrowest Raman peak with highest intensity,and the surface particles are larger and evenly distributed,indicating that the annealing at 700°C is more helpful to the formation of h-BN.The surface resistance for h-BN:Si films are as low as 2.0×10³?,and the p-n junction characteristics appear with the p-type Si substrate,further indicating that the Si element is successfully doped into the h-BN to form an n-type semiconductor.What's more,the conductivity of the films increases as the amount of Si doping increases.The growth annealing time can increase the area of the layered structure on surface of the films and make it to be more uniform and denser under the premise of stable structure.The grain size is significantly grown up to a maximum of 50?m².