Scalable CMOS back-end-of-line-compatible AlScN/two-dimensional channel ferroelectric field-effect transistors

Three-dimensional monolithic integration of memory devices with logic transistors is a frontier challenge in computer hardware. This integration is essential for augmenting computational power concurrent with enhanced energy efficiency in big data applications such as artificial intelligence. Despite decades of efforts, there remains an urgent need for reliable, compact, fast, energy-efficient and scalable memory devices. Ferroelectric field-effect transistors (FE-FETs) are a promising candidate, but requisite scalability and performance in a back-end-of-line process have proven challenging. Here we present back-end-of-line-compatible FE-FETs using two-dimensional MoS2 channels and AlScN ferroelectric materials, all grown via wafer-scalable processes. A large array of FE-FETs with memory windows larger than 7.8 V, ON/OFF ratios greater than 10(7) and ON-current density greater than 250 mu A um(-1), all at similar to 80 nm channel length are demonstrated. The FE-FETs show stable retention up to 10 years by extension, and endurance greater than 10(4) cycles in addition to 4-bit pulse-programmable memory features, thereby opening a path towards the three-dimensional heterointegration of a two-dimensional semiconductor memory with silicon complementary metal-oxide-semiconductor logic.

Automated summary

Three-dimensional monolithic integration of memory devices with logic transistors is crucial for enhancing computational power and energy efficiency in big data applications, such as artificial intelligence. However, there is still a need for reliable, compact, fast, energy-efficient, and scalable memory devices. In this study, back-end-of-line-compatible FE-FETs using two-dimensional MoS2 channels and AlScN ferroelectric materials were successfully demonstrated, showing promising performance and stability in memory retention and endurance. This research paves the way for the integration of two-dimensional semiconductor memory with silicon complementary metal-oxide-semiconductor logic in a three-dimensional heterostructure.