Memory window of highly c-axis oriented ferroelectric YMnO3 thin films

${\mathrm{YMnO}}_{\mathrm{3}}$ thin films have been sputtered with different ${\mathrm{O}}_{\mathrm{2}}$ partial pressures from 0% to 20%. Only the ${\mathrm{YMnO}}_{\mathrm{3}}$ sputtered without ${\mathrm{O}}_{\mathrm{2}}$ can be crystallized along (001) $c$ -axis orientation after annealing at $\text{870\hspace{0.05em}°}\mathrm{C}.$ Mixing 10%–20% ${\mathrm{O}}_{\mathrm{2}}$ partial pressure in the sputtering ambient, the excess ${\mathrm{Y}}_{\mathrm{2}}{\mathrm{O}}_{\mathrm{3}}$ in the ${\mathrm{YMnO}}_{\mathrm{3}}$ films suppresses the $c$ -axis oriented crystallization. Effects of crystallization on the ferroelectric properties of ${\mathrm{Pt/YMnO}}_{\mathrm{3}}{\mathrm{/Y}}_{\mathrm{2}}{\mathrm{O}}_{\mathrm{3}}\mathrm{/Si}$ (MEFIS) and ${\mathrm{Pt/YMnO}}_{\mathrm{3}}\mathrm{/Si}$ (MFS) gate capacitors have been investigated. The memory window of the MEFIS capacitor is enhanced by the $c$ -axis oriented crystallization of the ${\mathrm{YMnO}}_{\mathrm{3}}.$