Direct observation of excess carrier distribution in 4H-SiC power diodes

Author

Galeckas, A. ; Tomblad, O. ; Linnros, J. ; Breitholtz, B.

Author_Institution

Dept. of Electron., R. Inst. of Technol., Kista, Sweden

Volume

20

Issue

6

fYear

1999

fDate

6/1/1999 12:00:00 AM

Firstpage

295

Lastpage

297

Abstract

The first direct measurements of electrically injected carrier distributions in the base of 4H-SiC power diodes are reported. A novel approach of combining micron-resolution free-carrier absorption technique with optical imaging of e-h recombination radiation was applied to study the spatial and temporal plasma build-up. The excess carrier distributions both along and across the base region were examined during forward biasing within a 50-250 A/cm/sup 2/ range. The revealed local deviations of carrier density and lifetimes are attributed to inherent structural imperfections of the epilayer. Numerical device simulation demonstrated a good agreement with experiment and validated the importance of actual lifetime, contact, and emitter injection parameters to the overall plasma formation.

Keywords

carrier density; electron-hole recombination; power semiconductor diodes; semiconductor materials; semiconductor plasma; silicon compounds; SiC; carrier density; device simulation; e-h recombination radiation; electrically injected carrier distributions; emitter injection parameters; excess carrier distribution; forward biasing; local deviations; micron-resolution free-carrier absorption technique; overall plasma formation; plasma build-up; power diodes; structural imperfections; Absorption; Charge carrier density; Diodes; Electric variables measurement; Optical imaging; Plasma density; Plasma devices; Plasma measurements; Plasma simulation; Power measurement;

fLanguage

English

Journal_Title

Electron Device Letters, IEEE

Publisher

ieee

ISSN

0741-3106

Type

jour

DOI

10.1109/55.767103

Filename

767103