Journal of the Institute of Electronics Engineers of Korea SD (대한전자공학회논문지SD)

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The Hydrogenated Micro-crystalline Silicon(${\mu} c-Si:H$) Films Deposited by Hot Wire CVD Method

Hot Wire CVD법에 의한 수소화된 미세결정 실리콘(${\mu} c-Si:H$) 박막 증착

  • Lee, Jeong-Cheol (Renewable Energy Dept., Korea Institute of Energy Research) ;
  • Song, Jin-Su (Renewable Energy Dept., Korea Institute of Energy Research) ;
  • Park, Lee-Jun (Renewable Energy Dept., Korea Institute of Energy Research)
  • 이정철 (韓國에너지技術硏究所 代替에너지硏究部) ;
  • 송진수 (韓國에너지技術硏究所 代替에너지硏究部) ;
  • 박이준 (韓國에너지技術硏究所 代替에너지硏究部)
  • Published : 2000.08.01
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Abstract

This paper presents deposition and characterization of hydrogenated microcrystalline silicon (${\mu}c$ -Si:H) films on low cost glass substrate by Hot Wire CVD(HWCVD). The HWCVD ${\mu}c$ -Si:H films had deposition rates ranging from 2${\AA}$/sec to 35${\AA}$/sec with the variations of preparation conditions, which was 10 times higher than that of the films obtained from the conventional PECVD method. From the Raman spectroscopy, the prepared silicon films were found to be composed of the mixture of crystalline and amorphous phases. The crystalline volume fraction and average crystallite size, obtained from the Raman To mode peak near 520cm$^{-1}$, were 37-63% and 6-10 nm, respectively. The conductivity activation energy($E_a$) of the ${\mu}c$ -Si:H films, representing the difference of conduction band and Fermi level in an intrinsic semiconductors, increased from 0.22eV to 0.68eV with increasing pressure from 30mTorr to 300mTorr. The increase of $E_a$ with pressure indicates that the deposited films have properties close to intrinsic semiconductors, which is also proved with low dark conductivity of the ${\mu}c$ -Si:H deposited at 300mTorr. The tungsten concentration incorporated into films was about $6{\times}10^{16}atoms/cm^3$ in the samples prepared at wire temperature of 1800$^{\circ}C$.

열선 CVD(Hot Wire CVD)를 이용해 유리기판에 미세결정 실리콘(${\mu}c$ -Si:H) 박막을 증착시키고, 증착 조건에 따른 막의 특성변화를 관찰하였다. 열선 CVD법에 의한 ${\mu}c$ -Si:H막의 증착률은 조건변화에 따라 0.2nm/sec에서 3.5nm/sec사이의 값을 가졌으며, 기존의 PECVD법에 비해 10배 이상 높은 값이었다. Raman 특성으로부터 ${\mu}c$ -Si:H막은 비정질과 결정질의 두상이 혼합된 상태임을 알 수 있었으며, 평균 결정 립의 크기는 6-10nm, 결정체적분율은 37~63%범위였다. 막의 전도대와 Fermi 준위의 차를 나타내는 전도 활성화에너지(conductivity activation energy)는 30mTorr에서 0.22eV로 나타났으며, 압력에 따라 증가하여 300mTorr에서는 0.68eV의 값을 가졌다. 막의 활성화 에너지 증가는 높은 압력에서 증착된 막의 특성이 진성(intrisic)에 가까움을 의미하며, 이는 압력증가에 따른 암 전도도의 감소특성으로부터 확인할 수 있었다. 또한 이차이온질량분석으로부터 열선온도 1800$^{\circ}C$에서 증착시킨 막의 텅스텐 함유량은 $6{\times}10^{16}atoms/cm^3$임을 알 수 있었다.

Keywords

References

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