High Performance Metal Gate CMOSFETs with Aggressively Scaled Hf-Based High-k

Abstract

The optimization of MOSFET performance with Hf-based high-k and TiN metal gate is discussed. MOSFET performance and mobility of metal and poly gate on both high-k and SiO2 are compared. Optimization of the thickness and composition of Hf-silicate is discussed in terms of charge trapping and boron diffusion. The effect of metal gate thickness is also investigated. Appropriate dry and wet etch processes are found to effectively eliminate the metal foot and high-k undercut. Impressive Ion- Ioff characteristics have been achieved by applying an optimized gate-first CMOS flow to the high-k/metal stack. Ion = 1100µA/µm and 540µA/µm was attained for N and PMOSFETs with Vdd = 1.2V and Ioff = 100nA/µm.

Atomic layer deposition of B2O3/SiO2 thin films and their application in an efficient diffusion doping process

“…28 However, the notable thing is that the slope of the B 2 O 3 /up-SiO 2 lms is higher than that of SiO 2 lms, indicating the V FB shi to the (À) direction. This result agrees well with that in previous publications, which could be attributed to two possible reasons: (i) the presence of well-known positive xed charges in B 2 O 3 17,[29][30][31] and (ii) the formation of electric dipoles formed at the B 2 O 3 /SiO 2 interface. [32][33][34] Particularly, concerning the latter mechanism, Kita et al paid attention to the oxygen behavior at the interface, where the oxygen density difference is a driving force of the oxygen movement.…”