Sign-changing non-monotonic voltage gain of HfO2/Parylene-C/SrTiO3 field-effect transistor due to percolative insulator to two-dimensional metal transition

Abstract

Controlling the insulator-to-2D-metal transition is a promising key to overcome the scaling problem that silicon-based electronic devices will face in the near future. In this context, we examine the channel formation of SrTiO 3 -based solid-gated field-effect devices in which a 2D metal phase coexists with a semiconductor phase. A non-monotonic voltage-gain transfer characteristic with negative and positive slope regions is observed. We introduce a numerical model that helps to rationalize the experimental findings in terms of the established physics of field-effect transistors and percolation. Our numerical study not only reproduces the experimental results but also provides non-trivial predictions, which we verify experimentally.

Band offsets at amorphous-crystalline Al2O3–SrTiO3 oxide interfaces

“…The ability to obtain an insulating interface without significant oxygen vacancies is useful for several applications; insulator-STO interfaces with low ionic defect densities are sought for various devices, and currently complex routes are employed to form such interfaces. 52,53 Alignment of the energy scales of the different samples was done as follows: First, the energy scales of both the thick and thin Al2O3 layers were aligned so that the Al 2p3/2 peak of each is positioned at 74.4 eV 44 (dashed vertical line in Fig. 4).…”