Investigation of Buffer Traps in AlGaN/GaN Heterostructure Field-Effect Transistors Using a Simple Test Structure

Abstract

Abstract-We propose a new method which can extract the information about the electronic traps in the semi-insulating GaN buffer of AlGaN/GaN heterostructure field-effect transistors (HFETs) using a simple test structure. The proposed method has a merit in the easiness of fabricating the test structure. Moreover, the electric fields inside the test structure are very similar to those inside the actual transistor, so that we can extract the information of bulk traps which directly affect the current collapse behaviors of AlGaN/GaN HEFTs. By applying the proposed method to the GaN buffer structures with various unintentionally doped GaN channel thicknesses, we conclude that the incorporated carbon into the GaN back barrier layer is the dominant origin of the bulk trap which affects the current collapse behaviors of AlGaN/GaN HEFTs.Index Terms-AlGaN/GaN HFET, semi-insulating GaN buffer, bulk trap, carbon-doped GaN back barrier

The physical mechanism of dispersion caused by AlGaN/GaN buffers on Si and optimization for low dispersion

“…Therefore, rather than using a transistor as in [4][5], our method uses a 2DEG resistor (Fig. 1a) for sensing the electric field induced by the varying trap occupation in the buffer, similar to [6]. For the evaluation of the buffer induced dispersion, two distinct steps are used in the measurement procedure (Fig.…”

“…This allowed us to define a value for the "buffer dispersion", by calculating the ratio of the initial 2DEG resistance of an unstressed device to the values measured after stress ( ). Furthermore, performing this measurement procedure at varying temperatures, allowed us to perform trap spectroscopy [4][5][6] and, combined with a buffer DOE, allowed us to identify the physical location of the traps. The procedure was implemented using the Keysight B1505A parameter analyzer.…”

Contact Resistance and Leakage Current of GaN Devices with Annealed Ti/Al/Mo/Au Ohmic Contacts

“…GaN devices include Schottky barrier diodes [6] and high-electron-mobility transistors [7], with applications in power switching and RF amplification. Schottkycontact-controlled devices can achieve high-frequency operation, owing to the low capacitance.…”