硼掺杂对四面体非晶碳膜电导性能的影响

Effect of boron doping on the electrical conduction of tetrahedral amorphous carbon films

以单质硼和高纯石墨的混合粉末压制成型的靶材作为靶源,采用过滤阴极真空电弧技术制备不同硼含量的掺硼四面体非晶碳膜.分别采用四探针法、阻抗分析仪和电化学界面对薄膜的变温电导率、I-V特性和C-V特性进行了测试和研究.实验结果表明,当B含量由0增加至6.04 at%时,薄膜的室温电导率先逐渐增大而后逐渐减小,相应薄膜的电导激活能先逐渐减小而后逐渐增大,并在2.13 at%时分别出现最大和最小值1.42×10-7S/cm和0.1 eV.此外,掺硼四面体非晶碳/n型硅异质结的I-V曲线表现出典型的整流特性,表明p-n结二极管已经形成,且结两端的掺杂能级在空间上连续统一.

Boron doped tetrahedral amorphous carbon films were prepared on a filtered cathodic vacuum are deposition system by varying the weight percentage of boron in the mixed graphite cathodes. The electrical conductivity versus temperature, I-V characteristic and C-V characteristic for the films were measured by four-probe method, impedance/gain-phase analyzer, and electrochemical interface, respectively. As the boron content increases from 0 to 6.04 at%, the electrical conductivity of the films at room temperature increases gradually and then drops down, while the activation energy varies in the reverse. At the boron content of 2.13 at%, a maximum value of 1.42 × 10^-7 S/cm and a minimum value of 0.1 eV were obtained for the above two parameters, respectively. Furthermore, the rectification characteristics in the I- V curve indicated a p-n junction diode was formed for the boron doped tetrahedral amorphous carbon/n-type silicon heterojunction with uniform doping levels in the space at the two ends of the junction.