Atomically Thin Tin Monoxide-Based p-Channel Thin-Film Transistor and a Low-Power Complementary Inverter

Abstract

Atomically thin oxide semiconductors are significantly expected for next-generation cost-effective, energy-efficient electronics. A high-performance p-channel oxide thin-film transistor (TFT) was developed using an atomically thin p-type tin monoxide, SnO channel with a thickness of ∼1 nm, which was grown by a vacuum-free, solvent-free, metal-liquid printing process at low temperatures, as low as 250 °C in an ambient atmosphere. By performing oxygen-vacancy defect termination for the bulkchannel and back-channel surface of the ultrathin SnO channel, the presented p-channel SnO TFT exhibited good device performances with a reasonable TFT mobility of ∼0.47 cm 2 V −1 s −1 , a high on/ off current ratio of ∼10 6 , low off current of <10 −12 A, and a subthreshold swing of ∼2.5 V decade −1 , which was improved compared with the conventional p-channel SnO TFTs. We also fabricated metal-liquid printing-based n-channel oxide TFTs such as n-channel SnO 2 and In 2 O 3 -TFTs and developed ultrathinchannel oxide-TFT-based low-power complementary inverter circuits with the developed p-channel SnO TFTs. The full swing of voltage-transfer characteristics with a voltage gain of ∼10 and a power dissipation of <4 nW for p-SnO/n-SnO 2 and ∼120 and <2 nW for p-SnO/n-In 2 O 3 -CMOS inverters were successfully demonstrated.

The Significance of an In Situ ALD Al2O3 Stacked Structure for p‐Type SnO TFT Performance and Monolithic All‐ALD‐Channel CMOS Inverter Applications

“…The input and output pulses at a 100 Hz operating frequency (Figure 7e) indicated successful inverter operation. [ 19 ] The propagation delay time ( t P , calculated by [ t PLS + t PHL ]/2), of the inverter was 377 µs (The propagation delay times from low to high ( t PLH ) and high to low ( t PHL ) were 657 and 97 µs, respectively). From these results, we successfully identified a fabricated CMOS inverter with high performance despite degraded p‐type performances of SnO TFT ( V th 5.0 V, µ FE 0.28 cm 2 V −1 s −1 , and S ‐value 1.07 V decade −1 ), and large differences exist with IGZO TFT (Figure S2a, Supporting Information).…”

Vacuum-Free Liquid-Metal-Printed 2D Indium–Tin Oxide Thin-Film Transistor for Oxide Inverters

“…Figure summarizes the device performances of an oxide-CMOS inverter composed of the 2D-ITO-TFTs with p-channel 2D-SnO-TFTs, which is also fabricated with the liquid-metal route in air , (see Figure S9 for the optical microscopic image of 2D-SnO nanosheet). The p-channel 2D-SnO-TFT with ∼30 nm thick ALD-Al 2 O 3 gates showed reasonable TFT performances, such as μ SAT of ∼0.3 cm 2 V –1 s –1 , s -value of ∼2.3 V decade –1 , V th of −1 V, and on/off-current ratio of >10 4 (Figure a).…”

Emerging 2D Metal Oxides: From Synthesis to Device Integration

“…In a typical process, 2D SnO 2 can be obtained by liquid Sn printing method at ≈250 °C in ambient air but 2D SnO should be prepared at lower temperature (≈200 °C) to avoid the formation of SnO 2 . [ 46 ] The post‐annealing process can turn the SnO into SnO 2 . Therefore, to get desired oxidation‐state form, the great attention should be paid to the control of oxidation environment during the 2D metal oxide synthesis.…”