Piezoelectric Hafnium Oxide Thin Films for Energy-Harvesting Applications

This paper presents the piezoelectric properties of silicon doped hafnium oxide $(\text{Si}:\text{HfO}_{2})$ thin films and their superior suitability for energy harvesting applications. Various layer thicknesses from 10 nm to 50 nm, executed as single layer and in a laminate structure, are investigated. The piezoelectric coefficient $\mathrm{d}_{33,\mathrm{f}}$ of the samples is measured via double beam laser interferometry (DBLI) and converted into $\mathrm{d}_{33}$, based on a numerical simulation model. Values of up to $\mathrm{d}_{33}=73$ pm/V are obtained. Finally, the $\text{Si}:\text{HfO}_{2}$ films are electrically investigated by evaluating a relative permittivity between 37 and 47, respectively.