Electrical Characterization of Traps in AlGaN/GaN FAT-HEMT’s on Silicon Substrate by C-V and DLTS Measurements

摘要

We investigate high electron mobility transistors (HEMT’s) based on AlGaN/GaN grown by molecular beam epitaxy on Silicon substrates. The improvement of the performances of such transistors is still subject to the influence of threading dislocations and point defects which are commonly observed in these devices. Deep levels in FAT-HEMT’s are characterized by using Capacitance-Voltage (C-V) measurements, from which we can extract the barrier height and the donor concentration in the AlGaN layer. Deep Level Transient Spectroscopy (DLTS) Technique is also employed to identify defects in the heterostructure. Measurements reveal the presence of one electron trap with the activation energy E1 = 0.30 eV and capture cross-section σn = 3.59 10–19cm2. The localization and the identification of this trap have been discussed.