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Modeling of large area trench IGBTs: The effect of birds-beak

Accepted version
Peer-reviewed

Type

Article

Change log

Abstract

Three-dimensional modelling is becoming an increasingly prevalent technique to model more complex device structures. However, this alone is insufficient to accurately model large area devices. This study images the birds-beak in a commercial Insulated Gate Bipolar Transistor (IGBT) and highlights how this processing uncertainty, which impacts the channel properties, has a strong effect on the accuracy of TCAD simulations; resulting in the designer struggling to validate models and underappreciating the true behaviour of the device. It has been demonstrated that the birds-beak effect can be accounted for by a simple two-device model which allows for small-scale and large-scale device behaviours to be matched while limiting the computational effort for designers. The practical effects of birds-beaking on device performance has also been considered, and it has been shown that the variation in threshold voltage across the chip area results in a 32% reduction in short-circuit endurance time for the device. To overcome this, an alternative n+ emitter implantation is proposed, using a combination of arsenic and phosphorus, so that the device threshold is unaffected by the presence of birds-beaking and its variation during processing.

Description

Keywords

3-D technology computer-aided design modeling (3-D TCAD), birds-beak, endurance time, insulated gate bipolar transistor (IGBT), power devices, power electronics

Journal Title

IEEE Transactions on Electron Devices

Conference Name

Journal ISSN

0018-9383
1557-9646

Volume Title

66

Publisher

Institute of Electrical and Electronics Engineers (IEEE)

Rights

All rights reserved
Sponsorship
EPSRC (1724376)
Technology Strategy Board (102878)
This work was supported in part by UK Innovate Project Number 102878. E. M. Findlay was funded by an EPSRC Doctoral Training Partnership scheme (grant RG75686).