Semiconductor switch apparatus including isolated MOS transistors

A semiconductor switch apparatus comprising:

• an input terminal;
• an output terminal;
• an AC ground terminal;
• a DC ground terminal;
• a plurality of series MOS transistors connected in series between said input terminal and said output terminal;
• and
• a plurality of shunt MOS transistor connected in series between one of said input terminal and said output terminal and said AC ground terminal, said shunt MOS transistors being operated complementarily with said series MOS transistors;
• a semiconductor substrate;
• an insulating layer formed on said semiconductor substrate;
• a semiconductor layer formed on said insulating layer;
• each of said series MOS transistors being formed within a first region of said semiconductor layer surrounded by a first trench insulating layer,
• each of said shunt MOS transistors being formed within a second region of said semiconductor layer surrounded by a second trench insulating layer.