BEOL Compatible Indium-Tin-Oxide Transistors: Switching of Ultrahigh-Density 2-D Electron Gas Over 0.8 × 10<sup>14</sup>/cm<sup>2</sup> at Oxide/Oxide Interface by the Change of Ferroelectric Polarization
Mengwei Si, Anna Murray, Zehao Lin, Joseph Andler, Junkang Li, Jinhyun Noh, Sami Alajlouni, Chang Niu, Xiao Lyu, Dongqi Zheng, Kerry Maize, Ali Shakouri, Suman Datta, Rakesh Agrawal, Peide D. Ye
Abstract
In this work, we report back-end-of-line (BEOL) compatible indium-tin-oxide (ITO) transistors with ferroelectric (FE) Hf <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.5</sub> Zr <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.5</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> (HZO) as gate insulator. A tunable high-density 2-D electron gas over 0.8 \sf × 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">14</sup> /cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> is achieved at the HZO/ITO oxide/oxide interface because of the FE polarization, which is confirmed by I- V, positive up and negative down (PUND), and Hall measurements. Such high carrier density can be completely modulated and switched on and off by FE polarization switching, enabling high mobility ITO transistor with high ON-current and high ON/OFF ratio.