Novel Low Thermal Budget CMOS RMG: Performance and Reliability Benchmark Against Conventional High Thermal Budget Gate Stack Solutions

Abstract

Low thermal budget gate stack fabrication is a key enabler for upcoming CMOS technology innovations, such as sequential-3-D integration and CFETs. In this article, we discuss the impact on gate stack properties of the novel low-temperature atomic hydrogen and oxygen treatments that we have recently demonstrated on MOS capacitors. Next, we evaluate on a planar CMOS transistor platform various low thermal budget replacement gate (RMG) stacks based on (combinations of) these treatments, by benchmarking them against high-temperature RMG and gate-first counterparts. This first demonstration on both p-and n-channel transistors with properly tuned gate work functions allows to benchmark electron and hole mobilities and to assess stochastic variability (V-th mismatch), NBTI and PBTI reliability, and the performance (I-ON - I-OFF) and channel hot carrier reliability (safe operating area) of short-channel nMOS. We find that the atomic hydrogen treatment, originally developed to improve pMOS NBTI reliability, substantially boosts also the nMOS device performance and reliability due to a remarkably improved interfacial layer (IL) quality, matching high-temperature counterparts and thus providing a complete solution for low thermal budget CMOS RMG at a competitive EOTs.