Influence of different peripheral protections on the breakover voltage of a 4H-SiC GTO thyristor

Pierre Brosselard (1, 2) , Volker Zorngiebel (3) , Dominique Planson (1, 2) , Sigo Scharnholz (4) , J.-P Chante (1, 2) , Emil Spahn (4) , Christophe Raynaud (1, 2) , M. Lazar (1, 2)

1 CEGELY - Centre de génie électrique de Lyon
2 INSA Lyon - Institut National des Sciences Appliquées de Lyon
3 ISL - French-German Research Institute of Saint Louis
4 ISL - Institut franco-allemand de recherches de Saint-Louis

4H-SiC asymmetrical gate turn-off (GTO) thyristors have been developed using a PP-NP+ epitaxial layer structure, where P is a 35 µm thick p-type drift layer doped at 5E14 cm-3. The process sequence, described in details elsewhere, uses plasma etching steps (ECR and RIE) in order to expose interdigitated devices with a recessed gate structure. Knowing the difficulty in reaching the theoretical forward blocking capability of Vb = 6 kV, determined by numerical simulations using the finite element code MEDICITM, three different device terminations are realized. The first and simplest termination used is a MESA etched down to 12 µm deep into the drift layer. Better performance was expected by using a combination of MESA and Junction Termination Extension (JTE), but unfortunately, the JTE implantation was not well adjusted. Finally, etched guard ring (EGR) terminations are realized etching five 2 µm wide grooves around the device periphery through the n-base layer. The electric characteristics of the devices with all the three terminations are presented and discussed using the results of numerical simulations. The highest breakover voltage measured amounts to 4.0 kV, approaching the theoretical limit of 0.63·Vb, calculated for plane parallel junction.

Domaines: Energie électrique

Pierre Brosselard, Volker Zorngiebel, Dominique Planson, Sigo Scharnholz, J.-P Chante, et al.. Influence of different peripheral protections on the breakover voltage of a 4H-SiC GTO thyristor. International Conference on Silicon Carbide and Related Materials (ICSCRM'2003), Oct 2003, Lyon, France. ⟨hal-02503456⟩