Redox‐Based Resistive Switching Memories – Nanoionic Mechanisms, Prospects, and Challenges

Transparent electronics is today one of the most advanced topics for a wide range of device applications. The key components are wide bandgap semiconductors, where oxides of different origins play an important role, not only as passive component but also as active component, similar to what is observed in conventional semiconductors like silicon. Transparent electronics has gained special attention during the last few years and is today established as one of the most promising technologies for leading the next generation of flat panel display due to its excellent electronic performance. In this paper the recent progress in n- and p-type oxide based thin-film transistors (TFT) is reviewed, with special emphasis on solution-processed and p-type, and the major milestones already achieved with this emerging and very promising technology are summarizeed. After a short introduction where the main advantages of these semiconductors are presented, as well as the industry expectations, the beautiful history of TFTs is revisited, including the main landmarks in the last 80 years, finishing by referring to some papers that have played an important role in shaping transparent electronics. Then, an overview is presented of state of the art n-type TFTs processed by physical vapour deposition methods, and finally one of the most exciting, promising, and low cost but powerful technologies is discussed: solution-processed oxide TFTs. Moreover, a more detailed focus analysis will be given concerning p-type oxide TFTs, mainly centred on two of the most promising semiconductor candidates: copper oxide and tin oxide. The most recent data related to the production of complementary metal oxide semiconductor (CMOS) devices based on n- and p-type oxide TFT is also be presented. The last topic of this review is devoted to some emerging applications, finalizing with the main conclusions. Related work that originated at CENIMAT|I3N during the last six years is included in more detail, which has led to the fabrication of high performance n- and p-type oxide transistors as well as the fabrication of CMOS devices with and on paper.

Oxide Semiconductor Thin‐Film Transistors: A Review of Recent Advances

In this paper, recent progress of binary metal-oxide resistive switching random access memory (RRAM) is reviewed. The physical mechanism, material properties, and electrical characteristics of a variety of binary metal-oxide RRAM are discussed, with a focus on the use of RRAM for nonvolatile memory application. A review of recent development of large-scale RRAM arrays is given. Issues such as uniformity, endurance, retention, multibit operation, and scaling trends are discussed.

Metal–Oxide RRAM

Numerous candidates attempting to replace Si-based flash memory have failed for a variety of reasons over the years. Oxide-based resistance memory and the related memristor have succeeded in surpassing the specifications for a number of device requirements. However, a material or device structure that satisfies high-density, switching-speed, endurance, retention and most importantly power-consumption criteria has yet to be announced. In this work we demonstrate a TaO(x)-based asymmetric passive switching device with which we were able to localize resistance switching and satisfy all aforementioned requirements. In particular, the reduction of switching current drastically reduces power consumption and results in extreme cycling endurances of over 10(12). Along with the 10 ns switching times, this allows for possible applications to the working-memory space as well. Furthermore, by combining two such devices each with an intrinsic Schottky barrier we eliminate any need for a discrete transistor or diode in solving issues of stray leakage current paths in high-density crossbar arrays.

A fast, high-endurance and scalable non-volatile memory device made from asymmetric Ta2O5−x/TaO2−x bilayer structures

https://iopscience.iop.org/article/10.1088/1468-6996/11/4/044305/pdf

Present status of amorphous In–Ga–Zn–O thin-film transistors

We have demonstrated self-aligned top-gate amorphous oxide TFTs for large size and high resolution displays. The processes such as source/drain and channel engineering have been developed to realize the self-aligned top gate structure. Ar plasma is exposed on the source/drain region of active layer to minimize the source/drain series resistances. To prevent the conductive channel, N 2 O plasma is also treated on the channel region of active layer. We obtain a field effect mobility of 5.5 cm2/V·s, a threshold voltage of 1.1 V, and a sub-threshold swing of 0.35 V/decade at sub-micron a-GIZO TFTs with the length of 0.67#x00B5;m. Furthermore, a-IZO TFTs fabricated for gate and data driver circuits on glass substrate exhibit excellent electrical properties such as a field effect mobility of 115 cm2/V·s, a threshold voltage of 0.2 V, a sub-threshold swing of 0.2 V/decade, and low threshold voltage shift less than 1 V under bias temperature stress for 3 hr.

High performance amorphous oxide thin film transistors with self-aligned top-gate structure

http://ma.ecsdl.org/content/MA2008-02/35/2317.full.pdf

High-Performance Oxide Thin Film Transistors Passivated by Various Gas Plasmas

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.

Low-Temperature-Grown Transition Metal Oxide Based Storage Materials and Oxide Transistors for High-Density Non-volatile Memory

A thin film transistor having an offset or a lightly doped drain (LDD) structure by self alignment and a method of fabricating the same comprises a substrate, a silicon layer disposed on the substrate and including a channel region, a source region and a drain region at both sides of the channel region, and offset regions, each offset regions disposed between the channel region and one of the source and drain regions at both sides of the channel region, a gate insulating layer covering the channel region and the offset regions disposed at both sides of the channel region excluding the source and drain regions, and a gate layer formed on the channel region excluding the offset regions. The thin film transistor has the structure in which an offset or LDD is obtained without an additional mask process.

Thin film transistor and method of fabricating the same

while still retaining a selective switch (transistor or diode) asthe data storage element. Thus for high-density applications,crossbar structures are ideal, whereas for non-volatility, resis-tance-change materials showthe best promise. In orderto rea-lize the fabrication of universal memory elements, it is im-perative to develop a class of materials and structures thatcombine robust processibility, strong scalability, and rapidprogramming speed with non-volatility and low power con-sumption. In our work, we have focused on defining just thestorage node portion of the devices, which utilize the resis-tance change within the film to store information via two dif-ferent stable resistance states. Here, we have attempted to de-termine the properties of such structures and to study themechanisms behind resistance RAM (RRAM) storage. OurTi-doped (0.1 wt %) NiO samples deposited at room temper-ature show favorable node characteristics such as the lowestwrite current reported thus far for a unipolar switching resis-tance-change-based device (ca. 10 lA). In addition, the pro-gramming speed is comparable to the write time of SRAM(10 ns). By combining this node element with an appropriateselect switch, such as a high-performance diode, a thresholddevice, or a two-terminal non-ohmic device, it becomes possi-ble to fabricate high-density universal memory.Indeed, the fabrication of universal memory as the nextgeneration of non-volatile memory is the logical goal for re-search in this field. In comparison to Flash and dynamicRAM (DRAM), which are the current industry standards,next generation memories must combine the non-volatility ofFlash with the high-speed performance of SRAM.

Huaxiang Yin

Papers

High performance amorphous oxide thin film transistors with self-aligned top-gate structure

High-Performance Oxide Thin Film Transistors Passivated by Various Gas Plasmas

Low-Temperature-Grown Transition Metal Oxide Based Storage Materials and Oxide Transistors for High-Density Non-volatile Memory

Thin film transistor and method of fabricating the same

Write Current Reduction in Transition Metal Oxide Based Resistance-Change Memory**