Tunneling in AlAl<inf>2</inf>O<inf>3</inf>Al MIM structures

Al–Al2O3–Al MIM structures are prepared by vacuum deposition of Al films in a pressure of 4 × × 10−3 Pa and oxidising them in air for 15 h at room temperature and then again depositing Al films over them. Tunneling studies on these Al–Al2O3‐Al structures are carried out from 77 to 300 K. The barrier parameters, viz. barrier height and barrier thickness, are evaluated using Simmon's theory (1963/64) and by the graphical method of Simmons' and Unterkofler (1963). It is observed that with a decrease of temperature, the barrier height increases and the barrier thickness decreases. Also the variation of the tunnel current density with temperature is in agreement with Simmons' equation. The variation of barrier height and thickness with temperature is attributed to band gap and ionic space charge variations in the dielectric and the existence of trap levels. Copyright © 1981 WILEY‐VCH Verlag GmbH & Co. KGaA