cBN/SiN-p异质结的电学性质研究

用射频溅射系统成功制备出 c BN/ Si N-p异质结 ,并系统研究了其电学性质。掺硫 (S)的 n型 c-BN薄膜用 1 3 .5 6MHz射频溅射系统沉积在 P型 Si(1 0 0 ) (8～ 1 5 Ω·cm)衬底上 ,靶材为 h-BN靶 (纯度达 99.99% )。溅射气体为氩气和氮气混合而成 ,固态硫 (S)通过加热蒸发混入工作气体 ,改变硫的加热温度可改变硫的掺杂剂量。为了测量异质结的电学性质 ,用真空蒸镀法在异质结表面蒸镀了 1 .5 mm× 2 .0 mm的铝电极。实验结果表明 ,c BN/ Si N-p异质结的 I-V曲线具有明显的整流特性 ,其正向导电特性的拟合结果表明异质结的电流输运符合安德森理论 ,c BN/ Si N-p异质结的 C-V曲线也和理想异质结的 C-V特性非常接近。得到的 c BN/ Si N-p异质结的自建势为 4.71 V,c-BN薄膜层中的施主浓度为 6.5 0× 1 0 1 4/ cm3。

Fabrication and Electrical Characterization of cBN/Si Heterojunctions

cBN/Si N p heterojunctions have been fabricated and characterized. n type cBN films were grown on p type Si wafers using RF reactive sputter, and obtained by adding S (sulfur) into working gas. The I V (current voltage) characteristics have obvious rectification. The fitting results show that the current transporting model for the cBN/Si N p heterojunctions is the same as Andersons transporting model. The C V characteristics are close to that of ideal heterojunctions. Based on the fitting results, the built in potential of the heterojunctions was determined, and the donor concentration is 6.5×10 14 /cm 3 in the cBN films.