Dual phase TiO(x)N(y)/TiN charge trapping layer for low-voltage and high-speed flash memory application.
Flash memory using a dual phase TiO(x)N(y)/TiN charge trapping layer has been fabricated and its electrical properties were investigated. The TiO(x)N(y)/TiN layer was formed by partial oxidation of a pre-deposited TiN layer, and the formation of TiO(x)N(y)/SiO(x)N(y) was confirmed by high-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) analyses. The enlarged conduction (deltaphi(c) = 3.6 eV) and valence (deltaphi(v) = 2.5 eV) band offsets of the TiO(x)N(y)/TiN to SiO2 enabled low-voltage (+/- 6 V) and fast programming/erasing (P: 2.7 x 10(4) V/s and E: -5.1 x 10(4) V/s) operations, while the transition layer suppressed the trapped charge leakage, giving rise to good 10-year data retention with less than 35% V(th) decay.