Method of producing a semiconductor device with an aluminum or aluminum alloy electrode
View Patent ↗A method of producing a semiconductor device that has a silicon substrate including a first major surface and a second major surface thereof, a front surface device structure being formed in a region of the first major surface, the method has a step of forming a rear electrode in a region of the second major surface, which includes evaporating or sputtering aluminum-silicon onto the second major surface to form an aluminum silicon film as a first layer of the rear electrode, the aluminum silicon film having a silicon concentration of at least 2 percent by weight when the thickness thereof is less than 0.3 μm.
1. A method of producing a semiconductor device that has a silicon substrate including a first major surface and a second major surface thereof, a front surface device structure being formed in a region of the first major surface, the method comprising:
forming a rear electrode in a region of the second major surface, including evaporating or sputtering aluminum-silicon onto the second major surface to form an aluminum silicon film as a first layer of the rear electrode, the aluminum silicon film having a silicon concentration of at least 2 percent by weight and a thickness of less than 0.3 μm.
2. The method of claim 1 , further comprising forming a buffer metal film on a surface of the aluminum-silicon film.
3. The method of claim 2 , further comprising:
forming a soldering metal film on a surface of the buffer metal film; and
forming a protective metal film on a surface of the soldering metal film.
4. The method of claim 2 , wherein the buffer metal film includes titanium or molybdenum.
5. The method of claim 1 , further comprising providing the silicon substrate having a thickness of 50 μm to 200 μm, before forming the aluminum-silicon film.
6. The method of claim 1 , further comprising producing a field stop type insulated gate bipolar transistor that includes, between the first major surface and the second major surface of the silicon substrate, a drift layer of a first conductivity type, a buffer layer of the first conductivity type, and a collector layer of a second conductivity type in a sequence from the first major surface, the collector layer being in contact with the aluminum-silicon film.