Low-temperature-grown transition metal oxide based storage materials and oxide transistors for high-density non-volatile memory

Abstract

An effective stacked memory concept utilizing all-oxide-based device components for future high-density nonvolatile stacked structure data storage is developed. GaInZnO (GIZO) thin-film transistors, grown at room temperature, are integrated with one-diode (CuO/InZnO)-one-resistor (NiO) (1D-1R) structure oxide storage node elements, fabricated at room temperature. The low growth temperatures and fabrication methods introduced in this paper allow the demonstration of a stackable memory array as well as integrated device characteristics. Benefits provided by low-temperature processes are demonstrated by fabrication of working devices over glass substrates. Here, the device characteristics of each individual component as well as the characteristics of a combined select transistor with a 1D-1R cell are reported. X-ray photoelectron spectroscopy analysis of a NiO resistance layer deposited by sputter and atomic layer deposition confirms the importance of metallic Ni content in NiO for bi-stable resistance switching. The GIZO transistor shows a field-effect mobility of 30 cm(2) V-1 s(-1), a V-th of +1.2V, and a drain current on/off ratio of up to 10(8), while the CuO/InZnO heterojunction oxide diode has forward current densities of 2 x 10(4) A cm(-2). Both of these materials show the performance of state-of-the-art oxide devices.