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 cm2 V−1 s−1, a Vth of +1.2 V, and a drain current on/off ratio of up to 108, while the CuO/InZnO heterojunction oxide diode has forward current densities of 2 × 104 A cm−2. Both of these materials show the performance of state‐of‐the‐art oxide devices.

Physics-Based SPICE Model of a-InGaZnO Thin-Film Transistor Using Verilog-A

“…As a representative amorphous oxide semiconductor (AOS) material, amorphous InGaZnO (a-IGZO) has been studied and developed intensively as an active layer of thin-film transistors (TFTs) for switching/driving devices in flexible e-paper, transparent/lightweight display backplanes for active-matrix liquid crystal display (AMLCD) and/or active-matrix organic light-emitting diode display (AMOLED) [1,2], stackable logic circuitry [3], and 3-D memories [4]. In order to design and integrate various innovative systems using AOS TFTs, the circuit simulation with physics-based and processcontrolled parameters, not fitting parameters, is indispensible for process/structure optimization.…”

P‐26: High Capacity Memory using Oxide Based Schottky Diode and Unipolar Resistive Array

“…Besides, T. Nishijima et al reported the low-power display system through the non-volatile memory (NVM) array [8]. The RRAM devices are next-generation NVM alternative technologies owing to its simple device structure, low power consumption, favorable scalability and fast switching [9,10]. However, to implement high density 4F 2 cross point array, a non-linear selection device such as diode is needed to suppress the sneak current through the unselected cells which causes readout errors.…”

Comparator and half adder design using complementary resistive switches crossbar

“…Otherwise M = "1". When three voltage variables are applied to T 1 , T 2 , T 3 respectively, the next states, and its present states S 1 , S 2 are described by (2). The output M and inputs T 1 , T 2 , T 3 , and present states S 1 , S 2 is described by (3).…”

“…However, sneak path problem limits the size of the arrays and increases their power consumption. To solve the sneak path problem, various solutions were proposed, such as P-N junction type diode [2], Schottky type diode [3], complementary resistive switches (CRS) [4]. Among these proposed solutions, CRS is suitable for reducing parasitic current and making the application of large passive crossbar arrays feasible [4,5].…”