Characterisation of deep level trap centres in 6H-SiC p-n junction diodes

Deep level transient spectroscopy (DLTS) measurements were performed on sil icon carbide (6H-SiC) n(+)p(-)p(+) junction diodes in order to compare the electrical properties and quality of epitaxial layers in the implanted and the epitaxial emitter diodes, where the p(-)p(+) layers are the same. Four hole trap centres were detected on the implanted emitter diodes. Their ther mal activation energy's are 0.49, 0.6, 0.7 and 0.87 eV, respectively, refer red to the valence band. The last three trap centres are also observed on t he epitaxial emitter diodes. The origin of deep levels, with E-a=0.7 and 0. 87 eV, is still under investigation. The thermal activation energy and capt ure cross section (0.6 eV, 4.3 x 10(-15) cm(2)) is in good agreement with v alues reported for the boron-related D-centre. The trap centre with E-a=0.4 9 eV is associated to the ion-implantation process of the n(+) layer. Doubl e deep level transient spectroscopy measurements (DDLTS) have been performe d to accurately profile this last defect through the depletion region. Its trap concentration N-T(x) as a function of the depletion region width indic ates that this defect is located near the n(+)/p(-) junction. (C) 1999 Else vier Science S.A. All rights reserved.