Review Literature for Mosfet Devices Using High-K

With the advancement of MOS devices over 40 years ago, SiO2 has been used as an efficient gate dielectric. The need for increased speed at constant power density has led to shrinking of MOSFET dimensions and as per scaling rules; the oxide thickness is also reduced in step. With scaling reaching sub nanometer technology nodes, the introduction of novel materials became inevitable as scaling of SiO2 raises a serious concern in terms of tunneling current and oxide breakdown. High-k gate technology is emerging as a strong alternative for replacing the conventional SiO2 dielectrics gates in scaled MOSFETs for both high performance and low power applications. High-k oxides offer a solution to leakage problems that occur as gate oxide thickness’ are scaled down. Therefore, it is necessary to replace the SiO2 with a thicker layer of higher dielectric constant. Considering scaling issues various criteria of selection of dielectric and detailed study of various dielectrics are studied in this paper. Since high-k dielectric is not as favorable as the native oxide (SiO2) some factors need to be considered while replacing SiO2 by other dielectric materials.