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X-ray diffraction imaging of fully packaged n–p–n transistors under accelerated ageing conditions

Tanner, Brian K.; Danilewsky, Andreas; McNally, Patrick J.

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Authors

Andreas Danilewsky

Patrick J. McNally



Abstract

X-ray diffraction imaging was used to monitor the local strains that developed around individual n–p–n bipolar transistors within fully encapsulated packages under conditions of extremely high forward bias to simulate accelerated ageing. Die warpage associated with the packaging was observed to relax systematically as the polymer became viscous due to the temperature rise associated with the dissipation of heat in the transistor. The direct image size and intensity from the individual transistors were interpreted in terms of a model in which local thermal expansion is treated as a cylindrical inclusion of distorted material, contrast arising principally from lattice tilt. The extension of the thermal strain image along the emitter with increasing power dissipation was ascribed to the effect of current crowding in the emitter region. Weaker large-area contrast associated with the base–collector region was interpreted as arising from the smaller change in effective misorientation at the high X-ray energy of thermal lattice dilation in the base region.

Citation

Tanner, B. K., Danilewsky, A., & McNally, P. J. (2022). X-ray diffraction imaging of fully packaged n–p–n transistors under accelerated ageing conditions. Journal of Applied Crystallography, 55(5), 1139-1146. https://doi.org/10.1107/s1600576722007142

Journal Article Type Article
Acceptance Date Jul 11, 2022
Online Publication Date Aug 30, 2022
Publication Date 2022-10
Deposit Date Oct 12, 2022
Publicly Available Date Mar 28, 2024
Journal Journal of Applied Crystallography
Print ISSN 0021-8898
Electronic ISSN 1600-5767
Publisher International Union of Crystallography
Peer Reviewed Peer Reviewed
Volume 55
Issue 5
Pages 1139-1146
DOI https://doi.org/10.1107/s1600576722007142

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