Pinched doped well for a junction field effect transistor (JFET) isolated from the substrate

A method of manufacturing a field effect transistor (FET) structure, comprising:

• forming a pinched doped well, wherein the pinched doped well is doped with a first type of dopant;
• forming an oppositely-doped region surrounding the pinched doped well such that the FET structure is isolated from a surrounding material, wherein the oppositely-doped region is doped with a second type of dopant having an opposite polarity of the first type of dopant;
• and
• forming an isolation electrode coupled to the oppositely-doped region such that the FET structure is isolated from a substrate and such that a voltage bias of the FET structure is independent from a voltage bias of the substrate.

A semiconductor device, comprising:

• a substrate comprising dopant of a first polarity;
• a deep well comprising dopant of a second polarity opposite from the first polarity, wherein the deep well is buried in the substrate;
• and
• lateral wells in the substrate that extend from the deep well to approximately a top of the substrate, wherein the lateral wells comprise dopant of the second polarity,
• wherein the lateral wells and the deep well isolate a portion of the substrate from a remainder of the substrate, and
• wherein the isolated portion of the substrate comprises a channel of a field effect transistor (FET).

A microelectromechanical system (MEMS) microphone package, comprising:

• an acoustic port configured to receive ambient sounds;
• a diaphragm acoustically coupled to the acoustic port and configured to convert the ambient sounds to electronic signals;
• and
• an amplifier coupled to the diaphragm and configured to process the electronic signals, wherein the amplifier comprises one or more field effect transistors (FETs), at least one of the one or more FETs comprising:
• a pinched doped well, wherein the pinched doped well is doped with a first type of dopant;
• and
• an oppositely-doped region surrounding the pinched doped well such that the FET structure is isolated from a surrounding material, wherein the oppositely-doped region is doped with a second type of dopant having an opposite polarity of the first type of dopant.