Epitaxial fabrication and memory effect of ferroelectric LiNbO3 film/AlGaN/GaN heterostructure

Abstract

A metal-ferroelectric-semiconductor structure was fabricated epitaxially by depositing a ${\text{LiNbO}}_3$ film on the surface of the AlGaN/GaN template with two dimensional electron gas (2DEG). The capacitance-voltage characteristics were studied. Counterclockwise memory windows could be observed clearly. The size of the window first increased with increasing forward bias $\left(V_{\text{max}}\right)$ and reached a maximum of 2.5 V when $V_{\text{max}}=6\text{V}$ . This was attributed to the switchable ferroelectric polarization modulating on 2DEG. When $V_{\text{max}}$ exceeded 6 V, the window decreased due to electron injection. These results indicated that ferroelectric films combined with AlGaN/GaN would hold promise for next-generation memory devices.