Low substrate temperature deposition of amorphous and microcrystalline silicon films on plastic substrates by hot-wire chemical vapor deposition

Amorphous and microcrystalline silicon films were deposited by radio-freque ncy plasma enhanced chemical vapor deposition (rf-PECVD) and hot-wire chemi cal Vapor deposition (HW-CVD) on plastic (polyethylene terephthalate-PET) a t 100 degrees C and 25 degrees C. Structural properties of these films were measured by Raman spectroscopy. Electronic properties were measured by dar k conductivity and photoconductivity. For amorphous silicon films deposited by rf-PECVD on PET, photosensitivities > 10(5) were obtained at both 100 d egrees C and 25 degrees C, For amorphous silicon films deposited by HW-CVD, a photosensitivity of > 10(5) was obtained at 100 degrees C. Microcrystall ine silicon films deposited by HW-CVD at 95% hydrogen dilution had sigma(ph ) similar to 10(-4) Omega(-1) cm(-1), while maintaining a photosensitivity of similar to 10(2) at both 100 degrees C and 15 degrees C. Microcrystallin e silicon films with a large crystalline fraction (>50%) can be deposited b y HW-CVD all the way down to room temperature. All the films had good adhes ion and mechanical stability as neither adhesive nor cohesive failure was o bserved even when the substrates were bent elastically, (C) 2000 Elsevier S cience B.V, All rights reserved.