Study Of The Formation Mechanism And Preparation Of P-doped Diamond Films

In order to investigate the role of phosphorus（P）elements in doped diamond films.The formation mechanism and process of phosphorus-doped diamond films were studied in this paper by first-principles calculation and microwave plasma chemical vapor deposition（MPCVD）experiments.In terms of theoretical calculation,the formation energy and energy band of phosphorus substitution doped diamond are calculated by the method of first-principles calculation.The adsorption and migration behavior of phosphorus atoms on the hydrogen terminated diamond（001）surface with full hydrogen termination and active sites was investigated.According to the charge distribution,bader charge transfer and density of states（DOS）,the changes of charge and magnetic moment of P and C atoms before and after P atom adsorption and the bonding between them were analyzed in detail.In the experimental preparation,the preparation of phosphorus-doped diamond films was carried out with PH₃ as the dopant source,and characterized by Atomic Force Microscopy（AFM）,Scanning Electron Microscopy（SEM）and Raman spectroscopy.Through calculations and experiments,the following results were obtained:The calculation results show that the phosphorus atom can enter the diamond lattice in the form of substitution and cause deformation of the diamond lattice.After the P atom is doped,the diamond is changed from an indirect band gap to a direct band gap,and exhibits n-type semiconductor characteristics.Phosphorus atoms cannot be stably adsorbed on the full hydrogen-terminated diamond（001）surface,but can be stably adsorbed on the hydrogen-terminated diamond（001）surface with active sites,and can migrate on the diamond（001）surface with three active sites.The migration activation energy is approximately 1.72 eV.The experimental results show that the addition of PH₃ has a certain influence on the surface morphology of diamond films.As the flux of PH₃ increases,the diamond grain orientation changes from（111）to（110）,the size of the（110）oriented grains will increase.A proper amount of PH₃ can increase the growth rate of the film.As the PH₃ flux increases,the average surface roughness of the film gradually increases.