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

Write-once-read-many-times (WORM) characteristics of sol-gel InZnO (IZO) thin films are investigated in this paper. The Ag/IZO/n
⁺
-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
²
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
⁺
-Si WORM memory shows a superior read disturb immunity and a large memory window of 4 × 10
³
. The read endurance is over 10
⁴
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.