The Growth of Microcrystalline Thin Films Using ECR-PECVD

Download or read book The Growth of Microcrystalline Thin Films Using ECR-PECVD written by Yung Moo Huh and published by . This book was released on 2002 with total page 72 pages. Available in PDF, EPUB and Kindle. Book excerpt: A high rate growth method of hydrogenated microcrystalline silicon, [Mu]c-Si:H, and silicon-germanium, [Mu]c-(Si, Ge):H, has been developed with very low hydrogen dilution ratio on foreign substrates, using a remote electron cyclotron resonance - plasma enhanced chemical vapor deposition (ECR-PECVD) process. In this work, the key variable was the hydrogen dilution, ratio of hydrogen to silane, [H2]/[SiH4], which ranged from 3.3 to 10, adding helium systematically. Phase transition from amorphous to microcrystalline states was observed as the amount of added helium was varied. It has been found that hydrogenated microcrystalline silicon films with more than 70 % of crystalline volume fraction were formed at high growth rates of 3.2 Å/sec at low substrate temperature below 300°C from the mixture of silane and hydrogen with a low hydrogen dilution ratio of as low as 3.3. The addition of helium did not increase the growth rate significantly, but it quickly served as disrupting microcrystalline formation. In addition, the substrate temperature-dependent phase transition was observed. The structural, electrical and optical properties, by Raman shift, x-ray diffraction, dark and photo conductivity, activation energy of dark conductivity, and photosensitivity measurements, were investigated to grow good quality [Mu]c-Si:H films at the low hydrogen dilution ratio with high growth rates. The prominent peaks at 520 cm−1 from Raman Shift spectroscopy, crystalline peaks from x-ray diffraction pattern, small photosensitivity, and low activation energy of dark conductivity due to grain boundaries in microcrystalline silicon thin films indicated the characteristic of crystalline materials.