News Article

Neutrons Pep Up PHEMT Performance

A small dose of radiation improves the electrical characteristics of PHEMT devices used in the military industry.

French researchers have discovered that neutrons can actually improve some aspects of PHEMT performance, such as knee voltages and leakage currents.

“We were very surprised by this result", commented team member Bertrand Boudart from the University of Caen Lower Normandy. Previous studies by other researchers revealed that the electrical performance of PHEMT deteriorates at doses in excess of 1 x 1015 neutrons/cm2.

Understanding how PHEMT characteristics are influenced by neutron bombardment is important, because these devices are widely used in the military, nuclear and space industries.

MBE growth created the epitaxial structure (see figure), and Ni/AuGe/Ni/Au deposition formed the n- and p- contacts. The cap was then selectively etched away, before electron-beam lithography defined a Al/Ni/Au gate. A SiNx dielectric passivated the devices.

After irradiation of 1.2 x 1010 neutrons/cm2, the maximum drain-source current (IDS) increased from 121 to 128mA at a drain source voltage (VDS) of 2.5V and gate-source voltage (VGS) of 0.4V. The “knee voltage" (Vk) which is the value of VDS at the end of the saturation zone, decreased from 0.6 to 0.46V.

The researchers claim that these gains to PHEMT performance resulted from improvements in the ordering of structural impurities at the metal-semiconductor interface.

Further radiation doses of up to 3.3 x 1010 neutrons/cm2 had little effect on the peak drain-sourcecurrent, the knee voltage and the leakage current.

Coating the devices with a 1mm-thick sheet of lead ensured that gamma rays did not influence electrical performance of the devices.

Further details on this research are in the original publication which is available online:

‘Electronics Letters ‘, Volume 46, Issue 9, 2010, p650-652.

In a separate effort, this French team has investigated how gamma rays affect PHEMT characteristics; themaximum output power density was improved by a considerable 18 %.

GaN transistors have also been studied by the group. Boudart was tight-lipped, but he did describe the results as “interesting".

CS International to return to Brussels – bigger and better than ever!


The leading global compound semiconductor conference and exhibition will once again bring together key players from across the value chain for two-days of strategic technical sessions, dynamic talks and unrivalled networking opportunities.


Join us face-to-face between 28th – 29th June 2022

  • View the agenda.
  • 3 for the price of 1. Register your place and gain complementary access to TWO FURTHER industry leading conferences: PIC International and SSI International.
  • Email info@csinternational.net  or call +44 (0)24 7671 8970 for more details.

*90% of exhibition space has gone - book your booth before it’s too late!

Register


×
Search the news archive

To close this popup you can press escape or click the close icon.
×
Logo
×
Register - Step 1

You may choose to subscribe to the Compound Semiconductor Magazine, the Compound Semiconductor Newsletter, or both. You may also request additional information if required, before submitting your application.


Please subscribe me to:

 

You chose the industry type of "Other"

Please enter the industry that you work in:
Please enter the industry that you work in:
 
Live Event