Vertical Transport Control of Electrical Charge Carriers in Insulator/Oxide Semiconductor Hetero-structure

Abstract

The technology for electrical current passing through an insulator thin-film between two electrodes is newly getting spotlights for substantial potentials toward advanced functional devices including a diode and a resistive switching device. However, depending on an electrode-limited conduction mechanisms of the conventional devices, a narrow processing window for a thickness of the insulator thin-film and an inability to control a magnitude and direction of the currents are challenges to overcome. Herein, we report a new approach to enable electrical charge carriers to pass stably through a relatively-thick insulator layer and to control a magnitude and polarity of the currents by applying an oxide semiconductor electrode in a metal/insulator/metal structure. We reveal that the electrical conduction in our devices follows a space charge-limited conduction mechanism which mainly depends on the charge carriers injected from contacts. Therefore, characteristics of the current including a current value and a rectification ratio of input signal are precisely controlled by electrical properties of the oxide semiconductor electrode. The unique current characteristics in metal/insulator/oxide semiconductor structures give extendable inspirations in electronic materials science, even a prominent solution for various technology areas of electronics.

Effects of Unusual Gate Current on the Electrical Properties of Oxide Thin-Film Transistors

“…Thus, it can be reasonably deduced that the larger electrode area increases the probability of overlap with the trap sites inherently present inside the SiO 2 layer, and electrons are injected and transmitted through these overlapped trap sites 27 – 30 . In addition, this statistical dependence on the junction area of the vertical current is also consistent with our previous study 24 .…”

“…Recently we have studied that the unusual high vertical current flows through a relatively-thick insulator film in metal – insulator – oxide semiconductor structures. We have also verified that the magnitude and direction of the unconventional vertical current is also controlled by adjusting material properties of the top semiconductor electrode 24 . Herein, we have studied the origins of the unconventional vertical current through insulator films in more depth and the effect of the vertical current on the electrical performance of conventional oxide semiconductor TFT devices.…”

Verification of Charge Transfer in Metal-Insulator-Oxide Semiconductor Diodes via Defect Engineering of Insulator

“…In particular, most reported diodes have low rectifying ratio, which makes it difficult to control the leakage current. To solve these problems, we recently introduced MIOS (Metal-Insulator-Oxide Semiconductor) diodes 5 . Electronic devices that operate using the intrinsic trap in the insulator control the current magnitude and polarity by applying an oxide semiconductor electrode.…”

“…Lee et al . have introduced the outstanding MIOS diode properties such as high rectifying ratio and low leakage current that overcome the disadvantages of conventional p-n junction diodes and Schottky diodes 5 . However, these early-stage MIOS diodes are highly dependent on the semiconductor area used for the cathode 6 .…”

Advanced measurement and diagnosis of the effect on the underlayer roughness for industrial standard metrology

“…The finally estimated CR value of the HfO 2 overlayer in this dielectric system was 0.18 nm while the CR value of the underlayer was 0.27 nm. Moreover, in order to verify the effectiveness of the CR, we measured the leakage current through the metal-insulator-metal (MIM) diode structure 39,40 . As shown in Fig.…”