Bipolar semiconductor device and method for manufacturing such a semiconductor device

A method for manufacturing a bipolar semiconductor device with a semiconductor substrate, having at least a two-layer structure with layers of a first and a second conductivity type, a first main side, and a second main side,

• wherein one of the layers in the two-layer structure is a first base layer of the first conductivity type,
• wherein the first main side is structured as a MOS cell, and is arranged opposite of the second main side,
• wherein a first electrical contact is arranged on the first main side,
• wherein a second electrical contact is arranged on the second main side,
• wherein a second shorting layer of the first conductivity type is arranged on the base layer on the second main side, the shorting layer has a higher doping concentration than the base layer,
• wherein a patterned third layer of high conductivity material is arranged on the second shorting layer towards the second main side,
• wherein a fourth layer of the second conductivity type is arranged between the third layer and the second electrical contact,
• the manufacturing method comprising:
• forming a MOS cell structure on the first main side;
• applying particles of the first conductivity type or depositing a silicon layer of the first conductivity type on the second main side to create the at least one second shorting layer;
• depositing or growing a third layer of high conductivity materials such as a metal, graphene or silicides on the second shorting layer;
• wherein at least one step of the depositing or growing the third layer is performed through a mask;
• and
• depositing or growing a fourth layer of a second conductivity type to uniformly cover the third layer and portions of the second shorting layer not covered by the third layer;
• characterized in that,
• the fourth layer is either pre-doped or requires applying particles of the second conductivity type on the second main side.

A bipolar diode, comprising:

• a semiconductor substrate, having at least a two-layer structure with layers of a first and a second conductivity type, a first main side, and a second main side, wherein one of the layers is a first base layer of the first conductivity type,
• wherein the first main side is arranged opposite of the second main side,
• wherein a first electrical contact is arranged on the first main side,
• wherein a second electrical contact is arranged on the second main side,
• wherein a sixth buffer layer of the first conductivity type is arranged on the first base layer on the second main side, which sixth buffer layer has a higher doping concentration than the first base layer,
• wherein a patterned third high conductivity layer is arranged on the sixth buffer layer on the second main side, and
• wherein a fourth layer of the second conductivity type is arranged between the sixth buffer layer and the third highly conductive layer on one side, and the second electrical contact on the other side.