Write-Once-Read-Many-Times Characteristic of InZnO Oxide Semiconductor

Abstract

Write-once-read-many-times (WORM) characteristics of sol-gel InZnO (IZO) thin films are investigated in this paper. The Ag/IZO/n <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">+</sup> -Si WORM memory exhibits a poor read disturb immunity. Although a postannealing process is capable of improving the performance due to formation of a thin interfacial AgxO layer, the memory window is only 5 × 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> and the resistance in high resistance state degrades dramatically during read disturb testing. By replacing the Ag electrode with an Al electrode, without the postannealing process, the Al/IZO/n <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">+</sup> -Si WORM memory shows a superior read disturb immunity and a large memory window of 4 × 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> . The read endurance is over 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sup> cycles. X-ray diffraction, X-ray photoelectron spectroscopy, transmission electron microscopy, and energy dispersive spectroscopy were utilized to investigate the physical mechanisms of the WORM characteristics. The carrier conduction mechanisms were also explored.