Research On The Preparation And Electron Field Emission Property Of Diamond Film By Hot Filament Chemical Vapor Deposition

Diamond film has good chemical stability,low work function and electron affinity and other excellent physical and chemical characteristics,and it is a field emission cold cathode material that has a broad application prospect in areas such as vacuum microelectronics devices and graphic displays.Therefore,the study on the microstructure and field emission property of diamond films holds important academic value and application background.Based on the alteration of hot wire drawing device,the distance between the hot filament and the inlet,and the rotation of the sample stage,deposition of diamond thin film by hot filament chemical vapor deposition method in the basement single crystal silicon(100)surface;the microstructure of the diamond films were characterized by XRD,Raman and XPS,and etc.The electrical property and field emission property of the diamond films were characterized by EFE and Hall effects.It studied the influence reaction pressure,carbon source concentration,argon concentration and metal transition layer had on the micro structure and field emission property of the diamond film,and did a detailed analysis on the mechanism of the metal transition layer to improve the field emission property of diamond films.The main results are as below:Reaction temperature,carbon source concentration,argon concentration and metal transition layer all had a significant influence on the microstructure of diamond film,among which carbon source concentration had the most obvious regulation and controlled on the grain size of the diamond.With the decrease of the methane concentration,the grain size was 2.35 ?m when the methane concentration was 2.8%;the influence reaction gas pressure had on the deposition rate of the film was the most significant,as deposition rate increases with the decrease of the reaction pressure,and the deposition rate was up to 6.2 ?m/h at the reaction pressure of 1.5 kPa;the change of argon concentration and the addition of the metal transition layer had a significant control influence on microstructure and phase composition of the diamond film,which made non-diamond phase change significantly in diamond film.Through different processes controlled the structure of diamond film,achieving its field emission performance optimization,when the reaction gas pressure was 4 kPa,the methane concentration was 14.3%in the H2/CH4 reaction system,metal transition layer optimized electrical properties and field emission properties of micron diamond/metal/silicon composite film,conductivity of MCD/W/Si composite structure of the film was two orders of magnitude higher than the transition layer;open field strength was 5.4 V/?m,which was 44%lower than that of the non-transition layer;field emission current density could reach 1482 ?A/cm2 when the electric field intensity was 8.9 V/?m.The metal transition layer could not only improve interface characteristics and clear the interface channel of electron transport,but also increased the content of sp2 in the diamond film,and provided more conductive channels for the electronic transportation,which helped to obtain a higher field emission current,and then good field emission property should present.The nano-diamond films with excellent field emission properties prepared in the H2/CH4/Ar reaction system.With the increase of Ar concentration,the field emission properties was significantly enhanced;when the reaction gas pressure was 2 kPa,the methane concentration was 14.3%and the argon concentration was 45.7%,the diamond film exhibited the best field emission properties;open field was as low as 3.8 V/?m,and current density could achieve 2125 ?A/cm2 while electric field intensity was 6.5 V/?m.