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

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 cm(2) 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 10(9), extremely small hysteresis of 0 mV, low contact resistance of 0.44 k omega-mu m, 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.

Automated summary

The authors propose a novel vertically-stacked thin film transistor (TFT) architecture for heterogeneously complementary inverter applications, which consists of p-channel polycrystalline silicon (poly-Si) and n-channel amorphous indium tungsten oxide (a-IWO) with a smaller footprint than a planar structure. The electrical characteristics of the a-IWO TFT, including high mobility, low leakage current, and high on/off current ratio, make it well-suited for complementary metal-oxide-semiconductor technology applications. The vertically-stacked complementary field-effect transistors (CFET) exhibit high energy-efficiency and can increase the circuit density in a chip for next-generation semiconductor technology development.