Dielectrically-isolated integrated circuit

A switching apparatus, comprising:

• at least two bonding wires;
• gate, source and drain electrodes;
• and
• an impedance element connected between the gate and the source electrodes;
• the switching apparatus including an integrated circuit comprising a first semiconductor chip and a second semiconductor chip, each chip having a dielectric isolation region consisting essentially of an isolation film formed on an inner wall of an isolation groove disposed in each chip and a polysilicon film formed on the isolation film to bury the isolation groove, and an active region, electrically connected to said source and drain electrodes,
• wherein a top surface of the polysilicon film positioned at outer edge portions of each of the first and the second semiconductor chips is formed to have a resistivity so that an equivalent impedance between any two of the at least two bonding wires when the any two bonding wires contact the top surface of the polysilicon film is larger than a value of the impedance element.

A semiconductor chip comprising:

• a first active region;
• a second active region;
• and
• a dielectric isolation region,
• wherein the dielectric isolation region is disposed between and surrounds said first and second active regions and consists essentially of an isolation film formed on respective outer surfaces of the active regions and a polysilicon film formed on the isolation films to surround the respective active regions;
• wherein a top surface of the polysilicon film positioned at an outer edge portion of the semiconductor chip is formed to have substantially the same sheet resistivity as that of the polysilicon film disposed between the first and second active regions.