Ferroelectric metal-oxide-semiconductor capacitors using ultrathin single crystalline SrZrxTi1-xO3

TL;DR

This paper demonstrates the successful integration of ultrathin single crystalline SrZrxTi1-xO3 as a ferroelectric gate in MOS capacitors on Ge, showing robust ferroelectricity at nanoscale thicknesses, enabling advanced nanoelectronic devices.

Contribution

It introduces a method to create ferroelectric MOS capacitors using epitaxially grown SrZrxTi1-xO3 on Ge with ultrathin layers exhibiting strong ferroelectric properties.

Findings

Ferroelectric MOS capacitors with 5 nm thick SrZrxTi1-xO3 layers show a 2 V hysteretic window.

The ferroelectric properties are exceptionally robust at nanoscale thicknesses.

The development enables new possibilities for nanoelectronic device architectures.

Abstract

The epitaxial growth of multifunctional oxides on semiconductors has opened a pathway to introduce new functionalities to semiconductor device technologies. In particular, ferroelectric materials integrated on semiconductors could lead to low-power field-effect devices that can be used for logic and memory. Essential to realizing such field-effect devices is the development of ferroelectric metal-oxide-semiconductor (MOS) capacitors, in which the polarization of a ferroelectric gate is coupled to the surface potential of a semiconducting channel. Here we demonstrate that ferroelectric MOS capacitors can be realized using single crystalline SrZrxTi1-xO3 (x = 0.7) that has been epitaxially grown on Ge. We find that the ferroelectric properties of SrZrxTi1-xO3 are exceptionally robust, as gate layers as thin as 5 nm corresponding to an equivalent-oxide-thickness of just 1.0 nm exhibit a ~ 2 V hysteretic window in the capacitance-voltage characteristics. The development of ferroelectric MOS capacitors with nanoscale gate thicknesses opens new vistas for nanoelectronic devices.