Carrier lifetime investigation in 4H–SiC grown by CVD and sublimation epitaxy

✍ Scribed by P. Grivickas; A. Galeckas; J. Linnros; M. Syväjärvi; R. Yakimova; V. Grivickas; J.A. Tellefsen

• Book ID: 104420489
• Publisher: Elsevier Science
• Year: 2001
• Tongue: English
• Weight: 219 KB
• Volume: 4
• Category: Article
• ISSN: 1369-8001
• DOI: 10.1016/s1369-8001(00)00133-5

✦ Synopsis

Depth-resolved carrier lifetime measurements were performed in low-doped epitaxial layers of 4H silicon carbide samples. The technique used was a pump-and-probe technique where carriers are excited by an above-bandgap laser pulse and probed by free carrier absorption. Results from chemical vapour deposition samples show that lifetimes as high as 2 ms may be observed in the mid-region of 40 mm thick epilayers. For epilayers grown by the sublimation method decay transients were characterised by a fast (few nanoseconds) initial recombination, tentatively assigned to the 'true' lifetime, whereas a slow tail of several hundred microsecond decay time was assigned to trapping centres. From the saturation of this level at increased pumping we could derive the trapping concentration and their depth distribution peaking at the epilayer/substrate interface.