Experimental evidence of suppression on oxygen vacancy formation in Hf based high-κ gate dielectrics with La incorporation

Experimental evidence of suppression on oxygen vacancy formation in Hf based high-κ gate dielectrics with La incorporation is provided by using modified charge-pumping (CP) techniques. The original distribution of interface traps and bulk traps of pure HfO2 and HfO2/LaOx dielectric stack are extracted and compared by CP techniques. It is found that devices with HfO2/LaOx dielectric stack have higher interface trap but lower bulk trap density than those with pure HfO2. Especially, device with HfO2/LaOx dielectric stack is highly resistant to constant voltage stress, which can be attributed to the suppression on oxygen vacancy formation in Hf based high-κ gate dielectrics with La incorporation.