ALD-derived high-<i>k</i> ZrAlOx dielectrics for boosted performance of CNTs/ZTO CMOS inverter

Abstract

In this study, high-k dielectric zirconium aluminum oxide (ZrAlOx) and zirconium oxide (ZrO2) have been fabricated via atomic layer deposition. The effects of Al doping on the capacitance characteristics, leakage performance, surface roughness, and chemical composition of the ZrO2 and ZrAlOx gate insulators are investigated. ZnSnO thin-film transistors (ZTO TFTs) and carbon nanotube (CNT) TFTs have been integrated into the high-k dielectrics. By combining CNT TFTs with ZTO TFTs, complementary metal–oxide–semiconductor (CMOS) inverters have been developed, and the role of Al doping in enhancing the electrical characteristics of both TFTs and CMOS inverters has been investigated. The results show that, compared to CMOS inverters with ZrO2 gate insulators, those with ZrAlOx allow carriers to transport more smoothly at the interface and reduce carrier scattering, demonstrating a better performance with a smaller hysteresis (0.21 V), lower power consumption (5.0 × 10−8 W), higher gain (43.8), and better voltage transfer characteristics. This research provides theoretical support and practical value for the development of next-generation integrated circuits.