GaN Devices Modelling Group

GaN Devices 2

The GaN Devices Modelling Group is lead by Karol Kalna.

PhD Students: Khaled Ahmeda, Brendan Ubochi

Khaled AhmedaBrendan Ubochi


Wide-band-gap Gallium Nitride (GaN) is an ideal candidate for all applications requiring a fast carrier transport with a high breakdown voltage thank to its unique properties such as polarization, low
specific resistance, high electron mobility in channel, good thermal conductivity, and high critical electric field. We model GaN High Electron Mobility Transistors (HEMTs) device characteristics and look into reliability issues for radio frequency (RF) and power applications.

The GaN devices modelling group is based in Electronics Systems Design Centre (ESDC) of Swansea University.  Our simulation group consists of a number of research students (Soroush Faramerh, Khaled Ahmeda, Brendan Ubochi) currently running simulations on reliability issues and optimization of GaN HEMTs.

We are a part of the NRN funded project "Dynamic characterisation and modelling of RF GaN HEMTs" in collaboration with Cardiff University.

Schematic of AlGaN/GaN HEMT and its surface trapped charge (reliability issue) at off-state.

Schematic of AlGaN/GaN HEMT and its surface trapped charge (reliability issue) at off-state.

Research Tools

Simulation is a very flexible modelling approach in the area of GaN HEMTs where experimental techniques are not sufficient. We use commercial Silvaco simulation software with 30 interactive licenses.

Silvaco software provides unique capabilities including: (i) 2D/3D device modelling, (ii) drift-diffusion and hydrodynamic carrier transport modelling, (iii) surface defect analysis, (iv) bulk defect analysis, (v) transient simulation, (vi) thermal modelling, and (vii) wide-bandgap breakdown modelling.


Simulated ID-VG characteristics at indicated VD's for the 1μm gate length GaN(cap)/Al0.25G0.75N/AlN/GaN HEMT compared to experimental data.