SiN_x薄膜中硅纳米粒子的制备及表征

Fabrication and Characterization of Silicon Nanoparticles Embedded in SiN_x Films

通过等离子增强化学气相沉积(PECVD)法,以氨气和硅烷为反应气体,P型单晶硅和石英为衬底,低温下(200℃)制备了含硅纳米粒子的非化学计量比氮化硅(SiNx)薄膜.经高温(范围500～950℃)退火处理优化了薄膜结构.室温下测试了不同温度退火后含硅纳米粒子SiNx薄膜的拉曼(Raman)光谱、光致发光(PL)光谱及傅立叶变换红外吸收(FTIR)光谱,对薄膜材料的结构特性、发光特性及其键合特性进行了分析.Raman光谱表明.SiNx薄膜内的硅纳米粒子为非晶结构.PL光谱显示两条与硅纳米粒子相关的光谱带,随退火温度的升高此两光谱带峰位移动方向相同.当退火温度低于800℃时,PL光谱峰位随退火温度的升高而蓝移.当退火温度高于800℃时,PL光谱峰位随退火温度的升高而红移.通过SiNx薄膜的三种光谱分析发现薄膜的光致发光源于硅纳米粒子的量子限制效应.这些结果对硅纳米粒子制备工艺优化和硅纳米粒子光电器件的应用有重要意义.

Nonstoichiometric silicon nitride（SiNx） thin films with silicon nanoparticles were deposited on p-type crystalline silicon and quartz substrates at low temperature（200℃） using ammonia and silane mixtures by plasma enhanced chemical vapour deposition（PECVD）.The thin films structure was improved by high-temperature（range 500-950℃） annealing.The photoluminescence（PL） spectroscope,Raman spectra and Fourier transform infrared spectroscope（FTIR） of the SiNx thin films annealed at different temperatures were investigated at room temperature.The structure,luminescence and bonding configurations of the thin films were analyzed.Raman spectra showed that the silicon nanoparticles embedded in SiNx thin films were amorphous structure.Two PL spectra bands related to silicon nanoparticles were observed from PL spectra and their peak shifts were the same with increase of annealing temperature.For samples annealed below 800℃,the PL peaks show a blue-shift with increasing annealing temperature,while for the samples annealed over 800℃,an obvious red-shift of PL peaks is observed.Three kind of spectral analyses of the films show that photoluminescence of the thin films was attributed to quantum confinement effect of silicon nanoparticles.These results have valuable implications for the optimization of silicon nanoparticles fabrication process and silicon nanoparticles photoelectric device applications.