Vishay Semiconductor Gmbh

Christian Geng

Jochen Gerner

In order to achieve lateral current spreading between a current injecting or current collecting surface of an electrode and an active surface of an active region in a semiconductor device such as a light emitting diode, a layered semiconductor heterostructure is arranged between the electrode and the active surface. The heterostructure includes at least two semiconductor layers forming a heterojunction therebetween, whereby the semiconductor layers are composed of different semiconductor materials or different compositional proportions of the same compound semiconductor. An enrichment region for the majority charge carriers is formed in one of the layers adjacent the heterojunction, and a majority charge carrier energy band discontinuity exists at the heterojunction. Each enrichment region provides a strong lateral current spreading effect, such that a stacked arrangement of plural heterojunction layer pairs brings about a strong step-wise lateral current spreading. The light output and efficiency of a light emitting diode is substantially improved by incorporating such a current spreading heterostructure.

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Heilbronn, Germany

Christian Geng