摘要
采用热丝化学气相沉积法制备硼掺杂纳米金刚石(BDND)薄膜,并对薄膜进行真空退火处理,系统研究退火温度对BDND薄膜微结构和电学性能的影响.Hall效应测试结果表明掺B浓度为5000ppm(NHB)的样品的电阻率较掺B浓度为500ppm(NLB)的样品低,载流子浓度高,Hall迁移率下降.1000℃退火后,NLB和NHB样品的迁移率分别为53.3和39.3cm2·V-1·s-1,薄膜的迁移率较未退火样品提高,电阻率降低.高分辨透射电镜、紫外和可见光拉曼光谱测试结果表明,NLB样品的金刚石相含量较NHB样品高,高的硼掺杂浓度使薄膜中的金刚石晶粒产生较大的晶格畸变.经1000C退火后,NLB和NHB薄膜中纳米金刚石相含量较未退火时增大,说明薄膜中部分非晶碳转变为金刚石相,为晶界上B扩散到纳米金刚石晶粒中提供了机会,使得纳米金刚石晶粒中B浓度提高,增强纳米金刚石晶粒的导电能力,提高薄膜电学性能.1000℃退火能够恢复纳米金刚石晶粒的晶格完整性,减小由掺杂引起的内应力,从而提高薄膜的电学性能.可见光Raman光谱测试结果表明,1000℃退火后,Raman谱图中反式聚乙炔(TPA)的1140cm-1峰消失,此时薄膜电学性能较好,说明TPA减少有利于提高薄膜的电学性能.退火后金刚石相含量的增大、金刚石晶粒的完整性提高及TPA含量的大量减少有利于提高薄膜的电学性能.
Annealing of different temperatures was performed on boron-doped nanocrystaUine diamond （BDND） films synthesized by hot filament chemical vapor deposition （HFCVD）. Effects of annealing temperature on the microstructural and electrical properties of BDND films were systematically investigated. The Hall-effect results show that smaller resistivity and Hall mobility values as well as higher carrier concentration exist in the 5000 ppm boron-doped nanocrystalline diamond film （NHB） as compared with those in 500 ppm boron-doped nanocrystalline diamond film （NLB）. After 1000℃ annealing, the Hall mobility of NLB and NHB samples were 53.3 and 39.3 cm2.V-1 .s-1, respectively, indicating that annealing increases the Hall mobility and decreases the resistivity of the films. HRTEM, UV, and visible Raman spectroscopic results show that the content of diamond phase in NLB samples is larger than that in NHB samples because higher B-doping concentration results in a greater lattice distortion. After 1000℃ annealing, the amount of nano-diamond phase of NLB and NHB samples both increase, indicating that a part of the amorphous carbon transforms into the diamond phase. This provides an opportunity for boron atoms located at the grain boundaries to diffuse into the nano-diamond grains, which increases the concentration of boron in the nano-diamond grains and improves the conductivity of nanocrystalline diamond grains. It is observed that 1000℃ annealing treatment is beneficial for lattice perfection of BDND films and reduction of internal stress caused by doping, so that the electrical properties of BDND films are improved. Visible Raman spectra show that the trans- polyacetylene （TPA） peak （1140 cm-1） disappears after 1000℃ annealing, which improves the electrical properties of BDND films. It is suggested that the larger the diamond phase content, the better the lattice perfection and the less the TPA amount in the annealed BDND samples that prefer to improve the electrical properties of BDND films.
出处
《物理学报》
SCIE
EI
CAS
CSCD
北大核心
2013年第11期502-511,共10页
Acta Physica Sinica
基金
国家自然科学基金(批准号:50972129
50602039)
浙江省钱江人才计划(批准号:2010R10026)资助的课题~~
关键词
硼掺杂纳米金刚石薄膜
退火
微结构
电学性能
boron-doped nanocrystalline diamond films, annealing, microstructural properties, electrical properties
