Minority Carrier Lifetime Measurements in Specific Epitaxial 4H-SiC Layers by the Microwave Photoconductivity Decay

Abstract

We report on measurements of the minority carrier lifetime for different epitaxial 4H-SiC layers by using the microwave photoconductivity decay (µ-PCD) method. This is a non-contacting, non-destructive method very useful for the monitoring of recombination processes in semiconductor material. Distinct samples have been analyzed, giving different lifetime values. Transmittance and absorption spectra have also been carried out. The n-type layers, giving rise to a specific absorption peak near 470 nm, are not sensitive to optical excitation for the used wavelengths, as opposite to p-type layers whose lifetime values depend on thickness and doping.

Lifetime Measurement in n-Type 4H-SiC by Mean of the Microwave Phase-Shift

“…The designs of complex devices require the knowledge of several basic material parameters such as the minority carrier lifetime. Several teams developed tools for lifetime measurements, among them the Transient Free Carrier Absorption [1], Time Resolved Photo-Luminescence [2] and Microwave Photoconductivity Decay [3,4,5]. However all these methods mostly use pulsed lasers and are thus placed in non-equilibrium conditions.…”