Study of Phosphorus Doped Micro/Nano Crystalline Silicon Films Deposited by Filtered Cathodic Vacuum Arc Technique

Abstract

Phosphorus doped micro/nano crystalline silicon thin films have been deposited by the filtered cathodic vacuum arc technique at different substrate temperatures (Ts) ranging from room temperature (RT) to 350 ∘C. The films have been characterized by X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy, secondary ion mass spectroscopy, dark conductivity ( σD), activation energy ( ΔE) and optical band gap (E g). The XRD patterns show that the RT grown film is amorphous in nature but high Ts (225 and 350 ∘C) deposited films have a crystalline structure with (111) and (220) crystal orientation. The crystallite size of the higher Ts grown silicon films evaluated was between 17 to 31 nm. Raman spectra reveal the amorphous nature of the film deposited at RT whereas higher Ts deposited films show a higher crystalline nature. The crystalline volume fraction of the silicon film deposited at higher Ts was estimated as 65.7 % and 74.4 %. The values of σD, ΔE and E g of the silicon films deposited at different Ts were found to be in the range of 8.84 x 10 −4− 0.98 ohm −1cm−1, 0.06 - 0.31 eV and 1.31-1.93 eV, respectively. A n-type nc-Si/p-type c-Si heterojunction diode was fabricated which showed the diode ideality factor between 1.1 to 1.5.