Semiconductor device, reservoir computing system, and method for manufacturing semiconductor device

A reservoir computing system comprising:

• an input circuit;
• an output circuit;
• and
• a reservoir circuit connected between the input circuit and the output circuit,
• wherein the reservoir circuit includes the semiconductor device includes:
• a plurality of tunnel diodes, each of which includes a first semiconductor region of a first conductive type and a second semiconductor region of a second conductive type that is provided above the first semiconductor region, the second semiconductor region being a nanowire shape;
• an insulating film provided around a side surface of the second semiconductor region;
• a plurality of first electrodes, each coupled to the first semiconductor region;
• and
• a plurality of second electrodes, each coupled to the second semiconductor region,
• wherein the second electrode has a first surface that faces the side surface of the second semiconductor region across the insulating film, and
• a diameter on an upper surface of a second semiconductor region of a first tunnel diode of the plurality of tunnel diodes is different from a diameter on an upper surface of a second semiconductor region of a second tunnel diode of the plurality of tunnel diodes.

A method for manufacturing a semiconductor device, comprising processing of:

• forming a plurality of tunnel diodes, each of which includes a first semiconductor region of a first conductive type and a second semiconductor region of a second conductive type that is provided above the first semiconductor region and has a nanowire shape;
• forming an insulating film around a side surface of the second semiconductor region;
• forming a plurality of first electrodes, each coupled to the first semiconductor region;
• and
• forming a plurality of second electrodes, each coupled to the second semiconductor region,
• wherein the processing of forming the plurality of tunnel diodes includes processing of:
• forming a growth mask that has a plurality of openings with different diameters above a substrate;
• growing a plurality of the first semiconductor regions through the plurality of openings;
• and
• growing the second semiconductor region on each of the first semiconductor regions,
• the second electrode has a first surface that faces the side surface of the second semiconductor region across the insulating film, and
• a diameter on an upper surface of a second semiconductor region of a first tunnel diode of the plurality of tunnel diodes is different from a diameter on an upper surface of a second semiconductor region of a second tunnel diode of the plurality of tunnel diodes.