Research on photosensitive gate ferroelectric integrated GaN HEMT photodetector

Abstract

In this paper, we take advantage of the high sensitivity of two-dimensional electron gas concentration in the heterojunction channel of a GaN high electron mobility transistor (HEMT) to device surface states and gate voltages. By integrating a HEMT with ferroelectric materials with photovoltaic effects, a photo-sensitive gate HEMT photodetector based on ferroelectric integration is obtained. By exploring the ferroelectric and composite film sputtering growth epitaxial atmosphere, a high-performance PZT/ZnO composite ferroelectric film grown in an oxygen-containing atmosphere is obtained. Comparing the PZT and LiNbO3 (LN) ferroelectric thin films prepared with or without the buffer layer, the following conclusions are obtained. The quantum efficiency of the PZT/ZnO film increases by 240% and 596% at the peak of 300–400 nm, reaching 14.55%; the residual polarization of the PZT film obtained in an oxygen-containing atmosphere reaches 52.31 μC/cm2; the PZT/ZnO composite film has better fatigue characteristics. The GaN HEMT detector prepared by using magnetron sputtered PZT/ZnO as the sensing gate under the oxygen atmosphere has a photocurrent increment of 11.51 mA under ultraviolet light and a responsivity of 111A/W at 365 nm. At the same time, the device has τr = 0.12 s and τf = 8.3 s transient response. The research in this paper shows that a new structure photodetector based on a GaN HEMT has excellent ultraviolet light response, which provides a new research direction for the light detection mechanism.