Study of 3-nm Cylindrical GAAFETs with Variations in High-k Dielectric Gate-oxide Materials

Semiconductor devices using high k dielectric materials are widely adopted in memory and amplifier applications. Among the semiconductor devices gate all around-FET (GAAFET) is now the latest trend being used instead of other field effect transistors to serve the purpose of reducing the short channel effects (SCE). In this work, we examine the performance of a circular cross-section gate all around-field effect transistor (GAA-FET) with varying gate dielectric characteristics with high-k dielectric oxide materials (Al2O3, HfO2, HfSiO4, SiO2, Ta2O5, TiO2) across the 3-nm channel length. These simulations showed that even though the dielectric constant over the channel increases in value, both ION-IOFF ratio and transconductance upsurge. The obtained results indicated that raising the dielectric constant in a gate oxide reduces subthreshold slope (SS), increases amplification rate, and reduces threshold voltage (VTH) roll-off as well. The Silvaco TCAD ATLAS simulation was calibrated against experimental data from different works of literature. The higher the dielectric constant, the lower the SCEs. It is also found that TiO2 is dominating over the other materials selected for the simulation for a higher value of dielectric constant.