This book investigates the advancement and analysis of strained channel cylindrical gate-all-around (CGAA) FETs. The study explores a nano-scale design incorporating three ultrathin strained layers: two outer layers of strained silicon (s-Si) and a middle layer of strained silicon germanium (s-SiGe) forming a heterostructure-on-insulator (HOI) within the CGAA FET. These strained layers in the channel effectively confine quantum carriers thereby enhancing carrier mobility and reducing threshold voltage roll-off.