Transformation in Low‐Frequency Noise Spectra in GaN High‐Electron‐Mobility Transistors in Nonequilibrium Conditions

Abstract

It is known that flicker noise is the most intriguing noise component because it can be found in any type of material, object, device, or system. Despite the struggle of scientists to find a mutual model for the 1/f flicker noise law, there is still a challenge to describe the law in many cases. Herein, the studies of two‐level random telegraph signal (RTS) fluctuations analyzed for the state‐of‐the‐art high‐electron‐mobility transistors (HEMTs), fabricated based on AlGaN/GaN heterostructures, are presented. It is revealed that the shape of the fluctuations can be used to describe the formation of a 1 / f γ spectrum with γ = 1, 2, 3. The data demonstrate that the 1/f spectrum can be obtained as a result of the interactions of the carriers in parallel channels along the length of a system. Experimentally registered RTS fluctuations have a spectrum described by 1 / f γ behavior. The data are in good agreement with the theoretically predicted pulsed shape, allowing the generation of a 1/f spectrum. Based on the data analysis and the theoretical description of the fluctuations, the origin of 1/f fluctuations in nonequilibrium conditions is explained by interactions resulting in correlations of carriers in two parallel channels as the common feature in the HEMT devices.

New Approach for Enhancing Sensitivity in Liquid‐Gated Nanowire FET Biosensors Under Optical Excitation

“…At the same time, the correlation effect can be registered for a parallel conduction channel, which is electrostatically connected to the main channel, as in the case of high‐electron‐mobility transistor (HEMT) structures based on GaN/AlGaN. [ 25 ] In contrast to traditional, “dry” MOSFET structures, silicon FET structures with a liquid gate have a parallel conduction channel represented by a liquid, i.e., at the interface (Stern layer) between a thin subgate dielectric and the neutral region of the electrolyte. Features of the drift and diffusion of ions in this layer are determined by the specific Coulomb interaction between the ions and the interaction with the charge states at the interface.…”