증착 압력이 a-Si:H막의 전도도와 광학적 특성에 미치는 영향

전법주; 정일현

Journal of the Korean Industrial and Engineering Chemistry, Vol.10, No.1, 98-104, February, 1999

Export Citation

증착 압력이 a-Si:H막의 전도도와 광학적 특성에 미치는 영향

Effect of Deposition Pressure on the Conductivity and Optical Characteristics of a-Si:H Films

전법주, 정일현

초록

본 연구에서는 ECR플라즈마 화학증착법을 이용하여 반응기내 압력의 변화에 따라 수소화된 무정형 실리콘막을 증착하고 박막내 수소의 함량과 결합구조 및 전기적 특성을 조사하였다. 일반적인 CVD에 의해 제조된 a-Si:H막은 증착속도가 증가할수록 광감도는 감소하지만 ECR플라즈마의 경우 증착속도가 증가할수록 광감도가 향상되었다. 마이크로파 출력과 사일렌/수소 희석비, 반응기내 압력등이 동일한 실험 조건에서 증착시간에 따른 막의 두께는 선형적으로 증가하고 막내에 함유된 수소의 농도는 일정하지만, 반응시간이 짧은 경우 막내에 SiH₂결합이 SiH결합보다 많이 형성되어 광전도도를 저하시킬 수 있다. 반응기내 압력이 증가함에 따라 박막내에 SiH결합이 증가하여 광학 에너지 갭을 줄여 광전도도를 향상시킬 수 있었으나 암전도도의 증가로 광감도는 감소하였다. 따라서 양질의 박막을 얻기 위해서는 압력이 낮고 수소기체의 양이 적은 조건에서 성장시켜야 한다.

In this work, we investigated hydrogen content, bond structure, and electrical properties of a-Si:H films prepared by ECR plasma CVD as a function of pressure. In general, the photo sensitivity of a-Si:H films prepared by CVD method decreases as the deposition rate increases, but the photo sensitivity of a-Si:H films prepared by ECR plasma deposition method increases as the deposition rate increases. In the same condition of microwave power, the ratio of SiH₄/H₂, and pressure, though film thickness increases linearly with deposition time and hydrogen content in the film is constant, photo conductivity can be decreased because SiH₂ bond is made more than SiH bond in the short reaction time. According to increase pressure in the chamber, SiH bond in the film increase and optical energy gap decrease. So, photo conductivity can be increased. But photo sensitivity decreased as dark conductivity increase. It must be grown in the condition of low pressure and hydrogen gas for taking the a-Si:H film of high quality.

Keywords:Hydrogenated Amorphous Silicon;Deposition Rate;Hydrogen Content;Optical Energy Gap;Photo-dark Conductivity

[References]

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[2] Kitagawa M, Mori K, Ishihara S, Ohno M, Hirao T, Toshioka Y, Kohiki S, J. Appl. Phys., 53, 3269 (1983)

[3] Hishikawa Y, Tsuda S, Wakisaka K, Kuwano Y, J. Appl. Phys., 73, 4227 (1993)

[4] Caputo D, de Cesare G, Irrera F, Palma F, Rossi MC, Conte G, Nobile G, Fameli G, J. Non-Cryst. Solids, 73, 4227 (1993)

[5] Longeway PA, Estes RD, Weakliem HA, J. Phys. Chem., 88, 73 (1984)

[6] Hamasaki T, Ueda M, Chayara A, Hirose M, Osaka Y, Appl. Phys. Lett., 44, 600 (1984)

[7] Kobayashi K, Hayama M, Kauamoto S, Mike H, Jpn. J. Appl. Phys., 26, 202 (1987)

[8] Watanabe T, Azufumi K, Makatani M, Suzuki K, Sonobe T, Shimada T, Jpn. J. Appl. Phys., 25, 1805 (1986)

[9] Kitagawa M, Ishihara SI, Setsune K, Manabe Y, Hirao T, Jpn. J. Appl. Phys., 26, 231 (1987)

[10] Nakayama Y, Kondoh M, Hitsuishi K, Zhang M, Kawamura T, Appl. Phys. Lett., 57, 2297 (1990)

[11] Essick JM, Pool FS, Shink YH, J. Vac. Sci. Technol. A, 10, 521 (1992)

[12] Jeon BJ, Kang MS, Kim JY, Koo YS, Lim TH, Oh IH, An C, Jung IH, J. Mater. Chem. Phys., 51, 152 (1997)

[13] Jeon BJ, Kang MS, Kim JY, Lim TH, Oh IH, An C, Jung IH, Jpn. J. Appl. Phys., 2, L986 (1997)

[14] Scott BA, Reimer JA, Longeway PA, J. Appl. Phys., 54, 6853 (1983)

[15] Demichelis F, Mezzetti E, Tagliaferro A, Tresso E, J. Appl. Phys., 59, 611 (1986)

[16] Kruzelecky RV, Ukah C, Rakanski D, Zukokynski S, J. Non-Cryst. Solids, 103, 234 (1988)

[17] Yoshihiro H, Noboru N, Shinya T, Shoichi N, Yasuo K, Yukinori K, Jpn. J. Appl. Phys., 30, L108 (1991)

[18] Brodsky MH, Cardona M, Cuomo JJ, Phys. Rev., B, Condens. Matter, 16, 3556 (1977)