Effect of atomic layer deposition temperature on the performance of top-down ZnO nanowire transistors

• Main Authors: Mohamed Sulthan, Suhana (Author), Ditshego, Nonofo J. (Author), Gunn, Robert (Author), Ashburn, Peter (Author), Chong, Harold M. H. (Author)
• Format: Article
• Language: English
• Published: Springer New York LLC, 2014.
• Subjects: TK Electrical engineering. Electronics Nuclear engineering
• Online Access: Get fulltext

 This paper studies the effect of atomic layer deposition (ALD) temperature on the performance of top-down ZnO nanowire transistors. Electrical characteristics are presented for 10-μm ZnO nanowire field-effect transistors (FETs) and for deposition temperatures in the range 120°C to 210°C. Well-behaved transistor output characteristics are obtained for all deposition temperatures. It is shown that the maximum field-effect mobility occurs for an ALD temperature of 190°C. This maximum field-effect mobility corresponds with a maximum Hall effect bulk mobility and with a ZnO film that is stoichiometric. The optimized transistors have a field-effect mobility of 10 cm(2)/V.s, which is approximately ten times higher than can typically be achieved in thin-film amorphous silicon transistors. Furthermore, simulations indicate that the drain current and field-effect mobility extraction are limited by the contact resistance. When the effects of contact resistance are de-embedded, a field-effect mobility of 129 cm(2)/V.s is obtained. This excellent result demonstrates the promise of top-down ZnO nanowire technology for a wide variety of applications such as high-performance thin-film electronics, flexible electronics, and biosensing