We report experiments on single electron memory devices where the charging of a floating gate, which serves as a memory node, is done through aluminum oxide tunnel barriers and detected by a single electron transistor (SET) electrometer. The aluminum oxide tunnel barriers are fabricated through two different approaches. In one, the oxygen plasma oxidation of an as-deposited aluminum floating gate is used to grow aluminum oxide. In the other method. aluminum oxide is deposited on a titanium/gold floating gate by means of atomic layer deposition (ALD). Measurements performed on these devices at a temperature of 300 mK indicate the presence of a definite threshold for charging through the tunnel oxide barriers. A nonvolatile memory behavior is observed with each bit represented by about 15 electrons. (C) 2004 American Vacuum. Society.