Semiconductor device, manufacturing method thereof, protective element, and manufacturing method thereof

A manufacturing method of a semiconductor device, the method comprising:

• forming an epitaxial substrate by stacking a plurality of kinds of semiconductors over one semiconductor substrate by epitaxial growth;
• forming a field effect transistor of a first conductivity type in a first region of the epitaxial substrate by utilizing a stacking structure of the epitaxial substrate;
• forming a field effect transistor of a second conductivity type in a second region different from the first region of the epitaxial substrate by utilizing a stacking structure of the epitaxial substrate;
• and
• forming a protective element in a third region different from the first region and the second region of the epitaxial substrate by utilizing a stacking structure of the epitaxial substrate,
• wherein forming the protective element includes
• forming a first stacking structure by etching the epitaxial substrate by vertical etching that proceeds in a stacking thickness direction, and
• forming a second stacking structure by etching the epitaxial substrate by vertical etching that proceeds in a stacking thickness direction, and
• by forming the protective element, two PN junctions are formed on a current path formed between an upper end of the first stacking structure and an upper end of the second stacking structure via a base part of the first stacking structure and the second stacking structure.

A protective element comprising:

• an epitaxial substrate formed by stacking a plurality of kinds of semiconductors by epitaxial growth;
• a first stacking structure formed by etching the epitaxial substrate by vertical etching that proceeds in a stacking thickness direction;
• and
• a second stacking structure formed by etching the epitaxial substrate by vertical etching that proceeds in a stacking thickness direction,
• wherein two PN junctions exist on a current path formed between an upper end of the first stacking structure and an upper end of the second stacking structure via a base part of the first stacking structure and the second stacking structure.

A manufacturing method of a protective element, the method comprising:

• forming an epitaxial substrate by stacking a plurality of kinds of semiconductors by epitaxial growth;
• forming a first stacking structure by etching the epitaxial substrate by vertical etching that proceeds in a stacking thickness direction;
• and
• forming a second stacking structure by etching the epitaxial substrate by vertical etching that proceeds in a stacking thickness direction,
• wherein two PN junctions are formed on a current path formed between an upper end of the first stacking structure and an upper end of the second stacking structure via a base part of the first stacking structure and the second stacking structure by forming the epitaxial substrate, forming the first stacking structure, and forming the second stacking structure.