Power and temperature dependence of low frequency noise in AlGaN∕GaN transmission line model structures

Abstract

The low-frequency noise in AlGaN/ GaN transmission line model structures has been investigated for a wide range of ambient temperatures and dissipated powers. A deviation of low-frequency noise from a 1 / f dependence has been observed upon increasing the applied voltage. The effect correlates with the nonlinearity of current-voltage characteristics (CVC). The concept of nonequilibrium 1 / f noise has been introduced to explain 1 / f noise enhancement. A qualitative model connecting non-equilibrium noise with nonlinearity of the CVC via a common origin-nonuniform overheating of the structures-has been suggested. Furthermore, deviations of equilibrium noise from the 1 / f law at low temperatures have been observed and studied.

Low‐frequency noise in AlGaN/GaN HEMT structures with AlN thin film layer

“…2a have a broader frequency distribution than predicted by equation (1). To illustrate this fact, let us make a comparison of one of the normalized GR spectra with the theoretical curve calculated by (1) and presented in the corresponding coordinates (Fig.…”

“…A set of ohmic contacts in the TLM layout was processed afterwards with a width of 100 µm and a distance between contacts varying from 5 µm to 25 µm. As a difference with respect to structures investigated earlier [1] an additional 1.5 nm thick AlN barrier layer was grown between the Al 0.33 Ga 0.67 N barrier of 15 nm thickness and the GaN layer. The sheet concentration of the electrons in this channel measured by the Van der Pauw method was found to be 1.3⋅10…”

“…The properties of high electron mobility transistors (HEMTs) are changing in time due to degradation and transconductance dispersion as a result of trapping effects and electron transfer to the barrier states. In the case of structures with relatively low AlGaN barrier, a weak 2DEG localization may also lead to a number of undesired effects, such as a saturation of current and an increase of the 1/f noise level in the low-frequency region (non-equilibrium 1/f noise [1]). It was suggested that an additional thin AlN layer grown between AlGaN barrier and GaN layer may increase the degree of localization and improve the transport and noise properties of the HEMT structures.…”

Realization of AlGaN/GaN HEMTs on Si‐on‐polySiC substrates

“…A linear dependence is shown for dissipated powers ranging from 0.01 W to 0.5 W. As reported in Ref. [11], the contact spacings do not affect this dependence. Furthermore, no clear difference is observed between these devices realized on Si-on-polySiC and devices realized on thick silicon; a slightly lower resistance change is noticed for devices realized with similar structures grown on 4H-SiC substrate due to enhanced heat transfer towards the substrate.…”

“…To evaluate the influence of the heat transfer on the electrical properties, we measured the dependence of resistance change with the power dissipated inside Transmission Line Measurement (TLM) devices [11]. For this, I-V curves between ohmic contacts are measured and the resistance is calculated for each bias varying from 0.1 V up to 10 V typically.…”