Top-gate microcrystalline silicon TFTs processed at low temperature (<200 °C)

• Published in: Thin solid films 2005-09, Vol.487 (1), p.227-231
• Main Authors: Saboundji, A., Coulon, N., Gorin, A., Lhermite, H., Mohammed-Brahim, T., Fonrodona, M., Bertomeu, J., Andreu, J.
• Format: Article
• Language: English
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures; Exact sciences and technology; Low temperature; Low temperatures; Microcrystalline; Physics; Semiconductors; Silici; Silicon; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Temperatures baixes; Thin film transistors; Transistors
• ISSN: 0040-6090; 1879-2731
• DOI: 10.1016/j.tsf.2005.01.070

N-type as well P-type top-gate microcrystalline silicon thin film transistors (TFTs) are fabricated on glass substrates at a maximum temperature of 200 °C. The active layer is an undoped μc-Si film, 200 nm thick, deposited by Hot-Wire Chemical Vapor. The drain and source regions are highly phosphorus (N-type TFTs) or boron (P-type TFTs)-doped μc-films deposited by HW-CVD. The gate insulator is a silicon dioxide film deposited by RF sputtering. Al–SiO 2–N type c-Si structures using this insulator present low flat-band voltage,−0.2 V, and low density of states at the interface D it=6.4×10 10 eV −1 cm −2. High field effect mobility, 25 cm 2/V s for electrons and 1.1 cm 2/V s for holes, is obtained. These values are very high, particularly the hole mobility that was never reached previously.