过渡区p型氢化硅氧薄膜结构和光电特性的研究  

Structural and optoelectronic properties of p-type SiO:H films deposited in transition zone

作　　者：李同锴 徐征[1] 赵谡玲[1] 徐叙瑢[1] 薛俊明 

机构地区：[1]北京交通大学发光与光信息技术教育部重点实验室,北京100044 [2]石家庄铁道大学数理系应用物理研究所,石家庄050043 [3]河北汉盛光电科技有限公司,衡水053000

出　　处：《物理学报》2017年第19期235-242,共8页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:61575019)资助的课题~~

摘　　要：采用射频等离子体增强化学气相沉积技术,利用二氧化碳(CO_2)、氢气(H_2)、硅烷(SiH_4)和乙硼烷(B_2H_6)作为气源,制备出一系列p型氢化硅氧薄膜.利用拉曼光谱、傅里叶变换红外光谱和暗电导测试,研究了不同二氧化碳流量对薄膜材料结构和光电特性的影响,获得了从纳米晶相向非晶相转变的过渡区P层.研究表明:随着二氧化碳流量从0增加到1.2 cm^3·min^(-1),拉曼光谱的峰值位置从520 cm^(-1)逐渐移至480 cm^(-1).材料红外光谱表明,随着二氧化碳流量的增加,薄膜中的氧含量逐渐增加,氢键配置逐渐由硅单氢键转换为硅双氢键.P层SiO:H薄膜电导率从3S/cm降为8.3×10^(-6)S/cm.所有p型SiO:H薄膜的光学带隙(Eopt)都在1.82—2.13 eV之间变化.在不加背反射电极的条件下,利用从纳米晶相向非晶相转变的过渡区P层作为电池的窗口层,且在P层和I层之间插入一定厚度的缓冲层,制备出效率为8.27%的非晶硅薄膜电池.P-type hydrogenated silicon oxide（p-SiOx：H） films are prepared by radio frequency plasma enhanced chemical deposition with various CO2 flow rates. We use gas mixtures of carbon dioxide（CO2）, hydrogen（H2）, silane（SiH4） and diborane（B2H6） as reaction source gases. For all experiments the substrate temperature, pressure and power density are fixed at 200℃, 200 Pa and 200 mW/cm^2, respectively. The films are deposited on Corning Eagle 2000 glass substrates for optoelectronic measurements and on crystalline Si wafers for Fourier transform infrared（FTIR） measurement. The structural, optical and electronic properties of the films are systematically studied as a function of CO2 flow rate. The CO2 flow rate is varied from 0 to 1.2 cm^3·min^-1, with all other parameters kept constant. It is shown that with the CO2 flow rate increasing from 0 to 1.2 cm^3·min^-1, the Raman peak shifts from 520 cm^（-1） to 480 cm^-1 and corresponding crystalline volume fraction decreases from 70% to 0. In addition, the FTIR spectrum shows that the oxygen content increases from 0 to 17% and the hydrogen bond configuration gradually shifts from mono-hydrogen（Si-H） to di-hydrogen（Si-H2） and（Si-H2）n complexes in the film. What is more, with the incorporation of oxygen, the optical band gap of each of all p-type SiO：H films increases from 1.8 eV to 2.13 eV, while the dark conductivity decreases from 3 S/cm（nc-Si：H phase） to 8.310（-6）S/cm（a-SiOx：H phase）. Furthermore, the oxygen incorporation tends to disrupt the growth of silicon nanocrystals due to the created dangling bonds that arises from an increased structural disorder. This leads to microstructural evolution of SiO：H film from a single nanocrystalline phase into first a mixed amorphous-nanocrystalline and subsequently into an amorphous phase. At a certain threshold of CO2 flow rate, a transition from nanocrystalline to amorphous growth takes place. The transition from nanocrystalline to amorphous silicon is confirmed by Raman

关 键 词：射频等离子体增强化学气相沉积 过渡区p层 硅氧薄膜 光学带隙 

分 类 号：TM914.42[电气工程—电力电子与电力传动]