Field effect transistors having improved breakdown voltages and methods of forming the same

A field effect transistor comprising:

• a source of a first type of semiconductor;
• a drain of the first type of semiconductor, the drain comprising a first drain region of a first dopant concentration adjacent a second drain region, such that at least a portion of the second drain region is positioned between the first drain region and the source;
• an intermediate region of a second type of semiconductor intermediate the drain and source and spaced apart from the second drain region;
• a gate region disposed between the drain and source;
• a plug region of the second type of semiconductor disposed around the transistor;
• a buried layer of the second type of semiconductor disposed beneath the transistor;
• and
• a screening element disposed over the transistor, wherein the screening element is configured to shield the gate region from electric field gradients.

A method of forming a transistor, the method comprising:

• forming a well having a doping of a first type and a first doping concentration;
• forming a source and a drain in the well, the source and drain having a doping of a second type opposite that of the first type, wherein the source and drain are spaced apart by a first distance;
• forming an intermediate region in the well between the source and drain, the intermediate region having a doping of the first type and a second doping concentration, the second doping concentration greater than the first doping concentration, wherein the intermediate region is disposed between the source and drain and spaced apart from the drain by a second distance;
• forming a gate electrode above the intermediate region;
• forming a buried layer of first type of semiconductor beneath the transistor;
• forming a plug region of the first type of semiconductor around the transistor;
• and
• forming a screening element over the transistor, wherein the screening element is configured to shield the gate electrode from electric field gradients.