Sub-micron 3-D Electric Field Mapping in GaN Electronic Devices

Completed

Energy Efficiency(Residential and commercial)
Not Energy Related

Basic and strategic applied research

PHYSICAL SCIENCES AND MATHEMATICS (Physics)

Not Cross-cutting

Professor M Kuball
Physics
University of Bristol

Standard

EPSRC

01 May 2018

30 April 2022

48 months

£728,084

Info. & commun. Technol.

South West

NC : ICT

Professor M Kuball, Physics, University of Bristol

Project Contact, Compound Semiconductor Centre
Project Contact, United Monolithic Semiconductors (UMS), France
Project Contact, Qorvo, USA
Project Contact, M/A Com Technology Solutions (UK) Ltd
Project Contact, IQE Plc

AlGaN/GaN high electron mobility transistors (HEMTs) are a transformative technology for high-power density radio frequency applications, including radar, satellite and mobile communications. In addition, efficient power conversion systems based on GaN devices are a key enabling technology for the low carbon economy, including renewable energy generation and transport electrification. However, their full potential has not yet been realised because performance is de-rated to ensure stable long-term device operation. Experimental characterisation of the electric field distribution in these devices has been lacking, despite being identified as a primary driver of degradation phenomena including breakdown, charge trapping and self-heating. These processes occur in and around the device channel and particularly the sub-micron region under the gate and field plate where peak electric fields are located. The aim of this proposal is a step-change in electric field imaging of semiconductor devices, by developing an optical three dimensional (3-D) device analysis technique with nanometre-scale spatial resolution. The primary focus will be on electric field induced second harmonic generation (EFISHG) combined with solid immersion lenses (SILs). This will enable us to investigate key performance and reliability challenges including (i) the effect of buffer doping on the dynamic distribution of charge in the device layers which causes an undesirable memory effect, (ii) optimization of field plate geometry to manage peak electric fields, (iii) comparing electric field distributions during RF and DC operation to improve reliability forecasts. These are on the critical pathway to achieving a high performance reliable GaN HEMT device technology which exploits the full benefits of the material properties of GaN

18/02/19