Licentia Patent-verwaltungs Gmbh

Eupec Europaeische Gesellschaft Fuer Leistungshalbleiter Mbh & Co. Kg

Karl H Sommer

Alois Sonntag

Heinrich Schlangenotto

Wolfgang Pikorz

Holger Schoof

Edgar Borchert

Semiconductor element having a p-zone on the anode side and an adjacent,

An asymmetrical thyristor having an n.sup.+ pn.sup.- np.sup.- zone sequence whose functionability is not impaired and, in particular, whose reverse blocking characteristic is not degraded, if it fires after a forward current load and subsequent commutation before its turn-off time has expired due to the positive voltage increasing again. This insensitivity to refiring after commutation when falling below the turn-off time is realized by a flat rise of the doping concentration from the n.sup.- -type zone to the n-type zone, with the doping concentration in the n-type layer increasing approximately exponentially over a path of at least 50.mu.. In order to keep the forward off-state current low with a flat nn.sup.- junction, the thickness and doping of the n.sup.- -type layer are dimensioned such that at the highest intended forward off-state voltage the electric field intensity at the pn.sup.- junction is about 1.5.multidot.10.sup.5 V/cm, drops approximately linearly in the n.sup.- -type layer and, at the nn.sup.- junction, has approximately 1/4 of the value it has at the pn.sup.- junction. Methods for producing such a thyristor are also disclosed.

Asymmetrical thyristor and method for producing same

A thyristor with an amplifying gate including a silicon semiconductor body having n.sup.+ conductive main and auxiliary emitters at the cathode side, wherein a p.sup.+ zone is formed in a region of the p control base zone adjacent the surface of the semiconductor body between the auxiliary emitter zone and the main emitter zone. The p.sup.+ zone contacts the edge region of the main emitter zone which faces the auxiliary emitter zone, and preferably projects into the edge region, and forms a p.sup.+ n.sup.+ junction with the main emitter zone. Also, the p.sup.+ zone is laterally spaced from and does not contact the n.sup.+ auxiliary emitter zone.

Thyristor having n.sup.+ - main and auxiliary emitters and a p.sup.+

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Warstein, Germany

Karl H Sommer