Infineon Technologies Austria Ag

Daniel Pobig

Franz Hirler

Enrique Vecino Vazquez

Manfred Pippan

Patrick Schindler

A semiconductor device includes transistor cells formed along a first surface at a front side of a semiconductor body and having body regions of a first conductivity type, a drift region of a second conductivity type that is opposite from the first conductivity type and is disposed between the body regions and a second surface of the semiconductor body that is opposite from the first surface, and an emitter layer of the second conductivity type that is disposed between the drift region and a second surface of the semiconductor body, the emitter layer having a higher dopant concentration than the drift region, a metal drain electrode directly adjoining the emitter layer. The metal drain electrode comprises spikes extending into the emitter layer.

Semiconductor device with drain structure and metal drain electrode

According to an embodiment of a semiconductor device, the semiconductor device includes: transistor cells formed along a first surface at a front side of a semiconductor portion; a drain structure between the transistor cells and a second surface of the semiconductor portion opposite to the first surface, the drain structure forming first pn junctions with body regions of the transistor cells and including an emitter layer directly adjoining the second surface; and a metal drain electrode directly adjoining the emitter layer. An integrated concentration of activated dopants along a shortest line between the metal drain electrode and a closest doped region of a charge type of the body regions is at most 1.5E13 cm. Further semiconductor device embodiments are described.

An epitaxial layer is formed by epitaxy on a base substrate at a front side. From opposite to the front side, at least a portion of the base substrate is removed, wherein the base substrate is completely removed or a remnant base section has a thickness of at most 20 &#x3bc;m. Dopants of a first charge type are implanted from opposite of the front side into an implant layer of the epitaxial layer. A metal drain electrode is formed opposite to the front side. At least the implant layer is heated to a temperature not higher than 500&#xb0; C. The heating activates only a portion of the implanted dopants in the implant layer. After heating, an integrated concentration of activated dopants along a shortest line between the metal drain electrode and a closest doped region of a second, complementary charge type is at most 1.5E13 cm.

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Unterhaching, Germany

Daniel Pobig