Optical beam induced current measurements based on two-photon absorption process in 4H-SiC bipolar diodes

Hassan Hamad (1, 2) , Christophe Raynaud (1, 2) , Pascal Bevilacqua (1, 2) , Dominique Tournier (1, 2) , Bertrand Vergne (3) , Dominique Planson (1, 2)

1 EE - Ampère, Département Energie Electrique
2 INSA Lyon - Institut National des Sciences Appliquées de Lyon
3 ISL - Institut franco-allemand de recherches de Saint-Louis

Using a pulsed green laser with a wavelength of 532 nm, a duration pulse of ∼1 ns, and a mean power varying between 1 and 100 mW, induced photocurrents have been measured in 4H-SiC bipolar diodes. Considering the photon energy (2.33 eV) and the bandgap of 4H-SiC (3.2 eV), the generation of electron-hole pair by the conventional single photon absorption process should be negligible. The intensity of the measured photocurrents depends quadratically on the power beam intensity. This clearly shows that they are generated using two-photon absorption process. As in conventional OBIC (Optical Beam Induced Current), the measurements give an image of the electric field distribution in the structure under test, and the minority carrier lifetime can be extracted from the decrease of the photocurrent at the edge of the structure. The extracted minority carrier lifetime of 210 ns is consistent with results obtained in case of single photon absorption.

Mots clés: 4H-SiC; two-photon absorption; OBIC; bipolar diodes

Domaines: Energie électrique

Hassan Hamad, Christophe Raynaud, Pascal Bevilacqua, Dominique Tournier, Bertrand Vergne, et al.. Optical beam induced current measurements based on two-photon absorption process in 4H-SiC bipolar diodes. Applied Physics Letters, 2014, 104 (8), ⟨10.1063/1.4866581⟩. ⟨hal-01387924⟩