The identity and characteristics of the lifetime limiting defects in n-type 4H-SiC epitaxial layers were of particular current interest, due to the suitability of this material for high-power, solid-state switching devices. Much work was done in the past decade to identify the spectral signature and the local atomic structure of the defect that controlled the lifetime in this material. Until recently, it was concluded that two dominant electron traps, Z1/2 and EH6/7, both associated with a carbon vacancy, were controlling the lifetime. DLTS and optical studies show, however, that EH6/7 was not an important minority carrier trap, due to its small capture cross section for holes. Thus, Z1/2 acts alone as the lifetime limiting defect. The details of recombination at this trap were studied through the injection level and temperature dependence of the carrier lifetime and through carrier dynamics simulations that take into account the complex nature of the defect. The simulations shed light on the processes that dominate the recombination at Z1/2 over a large range of injection level and temperature.

Identification and Carrier Dynamics of the Dominant Lifetime Limiting Defect in n- 4H-SiC Epitaxial Layers. P.B.Klein: Physica Status Solidi A, 2009, 206[10], 2257-72