Microwave semiconductor device having coplanar waveguide and micro-strip line

A high frequency semiconductor device comprising:

• a substrate;
• a first metal layer disposed above the substrate and including:
• 1) a first metal strip;
• and
• 2) first and second ground metal plates sandwiching the first metal strip, each being isolated from the first metal strip;
• a first dielectric thin film that is selectively disposed on said first ground metal plate so as to form a concave, exposing surfaces of said first metal strip and another part of said first ground metal plate in a vicinity of said first metal strip;
• and
• a second metal layer including a second metal strip and disposed on said first dielectric thin film.

A semiconductor integrated circuit comprising:

• a substrate;
• first and second ground metal plates disposed above the substrate, spatially isolated from and facing to each other;
• a semiconductor active element sandwiched between said first and second ground metal plates, having first, second and third electrodes;
• an input metal strip configured to transmit a high frequency signal to the third electrode, sandwiched between said first and second ground metal plates;
• an output metal strip configured to receive the high frequency signal from the second electrode, sandwiched between said first and second ground metal plates;
• a first dielectric thin film disposed at least on a part of said first ground metal plate;
• a second dielectric thin film disposed at least on a part of said second ground metal plate;
• a first stub wiring disposed on said first dielectric thin film, connected to the input metal strip;
• and
• a second stub wiring disposed on said second dielectric thin film, connected to the output metal strip,
• wherein surfaces of the input and output metal strips are exposed so as to form a concave between the first and second dielectric thin films.

A semiconductor integrated circuit comprising:

• a substrate;
• first and second ground metal plates disposed above the substrate, spatially isolated from and facing each other;
• a semiconductor active element sandwiched between said first and second ground metal plates, having first, second and third electrodes;
• an input metal strip configured to transmit a high frequency signal to the third electrode, sandwiched between said first and second ground metal plates;
• an output metal strip configured to receive the high frequency signal from the second electrode, sandwiched between said first and second ground metal plates;
• a dielectric thin film unevenly disposed on said first ground metal plate, said input metal strip, said output metal strip and said second ground metal plate, the dielectric thin film having a thin layer formed on said input and output metal strips so as to form a concave above said input and output metal strips;
• a first stub wiring disposed on said dielectric thin film, connected to the input metal strip;
• and
• a second stub wiring disposed on said dielectric thin film, connected to the output metal strip,
• wherein a thickness of the dielectric thin film above the input and output metal strips differs from the thickness of the dielectric thin film under the first and second stub wirings.