News Article

First Current-collapse-free Vertical GaN Power Device

Chinese team report GaN-on-GaN power rectifier that outperforms lateral GaN-on-Si devices

Researchers from Zhejiang University (ZJU) have reported a vertical GaN-on-GaN power rectifier free from dynamic ON-resistance (RON) degradation, even at only 200ns after switching from high OFF-state bias up to 500V, outperforming the state-of-the-art lateral GaN-on-Si devices. The results were reported in IEEE Transactions on Power Electronics.

They claim that this is the first time that a current-collapse-free performance has been experimentally verified in a vertical GaN power device, by using a custom-designed double pulse test (DPT) circuit with minimised delay of 200ns and the capability for precise extraction of dynamic RON.

Conventional lateral GaN-on-Si devices have been confronted with the challenge of dynamic RON degradation arising from: (i) surface trapping that could easily degrade the 2DEG conductivity at a short distance from the III-nitride surface, and (ii) buffer trapping in the carbon-doped semi-insulating buffer stack where the deep-level traps could generate negative space charges and partially deplete the 2DEG.

By comparison, the vertical GaN-on-GaN device, featuring a vertical current flow and high-quality homo-epitaxial GaN drift layer with well controlled background/compensation doping, can fundamentally overcome the grand challenge of dynamic RON degradation, say the researchers.

The dynamic RON has been systematically and quantitatively evaluated using the DPT with a clamping circuit under different switching conditions, including: (1) OFF-state bias up to 500V, (2) OFF-state time within 10-6s ~102s, (3) high temperature up to 150degC, and (4) different load current levels.

The clamping circuit enables precise measurement of the low ON-state voltage after switching from high-voltage OFF-state, and the ultrashort delay of 200 ns in the custom-designed high-speed DPT can minimise possible trap recovery during measurement, leading to an accurate and precise extraction of dynamic RON. Under all the test conditions, the vertical GaN-on-GaN rectifier developed by ZJU is free from dynamic ON-resistance degradation at only 200 ns after switching from OFF-state, outperforming the state-of-the-art commercial lateral GaN-on-Si devices and showing great potential for high-frequency applications.

Figure 2 above shows time-resolved dynamic RON/static RON of (a) vertical GaN-on-GaN SBD developed by ZJU, (b) commercial lateral GaN-on-Si device A and (c) commercial lateral GaN-on-Si Device B with OFF-state time (tOFF) of 100 μs and OFF-state bias (VOFF) varying from 50 to 500 V.

Figure 3 above shows dynamic RON of the three types of GaN devices extracted at only 200 ns after switching from: (a) varying VOFF up to 500 V, (b) tOFF_Stress of 10-6~102 s and (c) high temperature up to 150 degC.

'Current-Collapse-Free and Fast Reverse Recovery Performance in Vertical GaN-on-GaN Schottky Barrier Diode' by Shaowen Han, Shu Yang, Rui Li et al; IEEE Transactions on Power Electronics

Search the news archive

To close this popup you can press escape or click the close icon.
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