Improved electrical and material characteristics of hafnium titanate multi-metal oxide n-MOSFETs with ultra-thin EOT (~8Å) gate dielectric application

Abstract

A novel approach of fabricating laminated TiO/sub 2//HfO/sub 2/ bi-layer multi-metal oxide dielectric was developed for high performance CMOS applications. Both layers showed negligible intermixing and no silicide formation. For the first time, ultra-thin EOT (/spl sim/8 /spl Aring/) was achieved with increased effective permittivity (k /spl sim/ 36) using the bi-layer dielectric. Leakage current characteristic was slightly higher than HfO/sub 2/ due to lower band offset of TiO/sub 2/. However, superior thermal stability (>950/spl deg/C), significantly reduced hysteresis characteristic, and comparable interface state density represent the high quality of TiO/sub 2//HfO/sub 2/ multi-metal oxide. Also, excellent subthreshold swing, increased transconductance, higher current drive, and -33% improved channel electron mobility compared to the control HfO/sub 2/ samples demonstrate the feasibility of new multi-metal oxide application for future CMOS technology.