Heterogeneous Integration of Atomically‐Thin Indium Tungsten Oxide Transistors for Low‐Power 3D Monolithic Complementary Inverter

Abstract

In this work, the authors demonstrate a novel vertically‐stacked thin film transistor (TFT) architecture for heterogeneously complementary inverter applications, composed of p‐channel polycrystalline silicon (poly‐Si) and n‐channel amorphous indium tungsten oxide (a‐IWO), with a low footprint than planar structure. The a‐IWO TFT with channel thickness of approximately 3‐4 atomic layers exhibits high mobility of 24 cm2 V−1 s−1, near ideally subthreshold swing of 63 mV dec−1, low leakage current below 10−13 A, high on/off current ratio of larger than 109, extremely small hysteresis of 0 mV, low contact resistance of 0.44 kΩ‐µm, and high stability after encapsulating a passivation layer. The electrical characteristics of n‐channel a‐IWO TFT are well‐matched with p‐channel poly‐Si TFT for superior complementary metal–oxide‐semiconductor technology applications. The inverter can exhibit a high voltage gain of 152 V V−1 at low supply voltage of 1.5 V. The noise margin can be up to 80% of supply voltage and perform the symmetrical window. The pico‐watt static power consumption inverter is achieved by the wide energy bandgap of a‐IWO channel and atomically‐thin channel. The vertically‐stacked complementary field‐effect transistors (CFET) with high energy‐efficiency can increase the circuit density in a chip to conform the development of next‐generation semiconductor technology.

Low‐Temperature Nanosecond Laser Process of HZO‐IGZO FeFETs toward Monolithic 3D System on Chip Integration

“…Accordingly, HfO 2 -based ferroelectric materials have great potential for use in data-intensive applications such as artificial intelligence, machine learning, edge computing, and in-memory structures. [13][14][15] Despite their high potential, current applications of HfO 2based ferroelectrics in memory devices with M3D integration face limitations due to the high-temperature annealing processes required, typically above 600 °C, which can cause thermal damage to underlying logic or input/output (I/O) circuits. To address this issue, various doping technologies, such as Zr, Al, Si, and Y, have been explored to enable phase transformation at lower temperatures via rapid thermal annealing (RTA).…”

“…Accordingly, HfO 2 ‐based ferroelectric materials have great potential for use in data‐intensive applications such as artificial intelligence, machine learning, edge computing, and in‐memory structures. [ 13 , 14 , 15 ]…”

Atomic Layer Deposition of WO3-Doped In2O3 for Reliable and Scalable BEOL-Compatible Transistors

“…However, high dopant concentrations of zinc oxide and gallium oxide can suppress the carrier mobility due to the decreased In 2 O 3 fraction in the films. Recent research has explored doping In 2 O 3 films with only several atom % tungsten in the form of tungsten oxides (WO 3 ) to form “IWO” as an alternative semiconducting oxide. , Prior literature suggested that this approach might leverage tungsten’s higher oxygen-bond dissociation energy to enhance threshold voltage stability without significant mobility loss . Reported IWO FETs have demonstrated exceptional on/off ratios, ultrathin channels, and highly scaled gate lengths.…”

“…Recent research has explored doping In 2 O 3 films with only several atom % tungsten in the form of tungsten oxides (WO 3 ) to form "IWO" as an alternative semiconducting oxide. 15,16 Prior literature suggested that this approach might leverage tungsten's higher oxygen-bond dissociation energy to enhance threshold voltage stability without significant mobility loss. 17 Despite such advancements, the method for depositing the IWO films reported to date is limited to sputtering, a physical deposition technique that involves using energetic species in a plasma struck near a source target or targets to deposit films at relatively low chamber pressures.…”