Sub-9 Å equivalent oxide thickness scaling using hafnium zirconate dielectric with tantalum carbide gate

Abstract

This paper reports on hafnium zirconate (HfxZr1−xO2) gate dielectric capacitance equivalent thickness scaling below 14 Å and equivalent oxide thickness scaling below 9 Å. This is accomplished by careful optimization of the HfxZr1−xO2 thickness and ammonia (NH3) postdeposition anneal (PDA) conditions with tantalum carbide (TaxCy) metal gate. Further, the various process schemes employed for the thickness scaling such as pretreatment, PDA, metal capping, and metal-oxide doping of HfxZr1−xO2 will be described. Finally, the attributes and possible mechanisms of NH3 PDA to reduce the thickness of interfacial layer and the thickness of the HfxZr1−xO2 layer for the oxide thickness scaling will be discussed.