Thermal behaviour of gate-less AlGaN/GaN heterostructures
For power applications, the dissipated power in GaN based devices becomes very significant and consequently can generate a very important self-heating effect in the component. The self-heating in the device increases considerably the lattice or the operating temperature and the transport properties are then degraded. To explain and to understand the physical phenomena observed in experiment for power components, it requires to introduce heating effects. The goal of this study is to estimate self-heating effects on the static characteristics of TLM (Transmission Line Model) AlGaN/GaN structures. For this objective, a developed physical thermal model is used in order to study the electrical and thermal phenomena in a coupled way. These studies are validated by electrical measurements regarding I-V characteristics and also by optic measurements using micro-Raman spectroscopy.
Structural studies using transmission electron microscopy have been made on 1-eV band-gap materials, lattice-matched to GaAs and Ge substrates, grown by metal-organic vapor-phase epitaxy for use in multijunction, high-efficiency solar cells.