Bipolar junction transistor (BJT) structure

A bipolar junction transistor (BJT) structure, comprising:

• a dielectric layer;
• a first well region formed over the dielectric layer;
• a second well region formed over the dielectric layer;
• a third well region formed over the dielectric layer, wherein the second well region is disposed between the first and third well regions;
• a plurality of first gate-all-around (GAA) field-effect transistors formed over the first well region, wherein source/drain features of the first GAA field-effect transistors are electrically connected together;
• a plurality of second GAA field-effect transistors formed over the second well region, wherein source/drain features of the second GAA field-effect transistors are electrically connected together;
• and
• a plurality of third GAA field-effect transistors formed over the third well region, wherein source/drain features of the third GAA field-effect transistors are electrically connected together,
• wherein the source/drain features of the first and third GAA field-effect transistors and the first and third well regions have a first conductivity type, and the source/drain features of the second GAA field-effect transistors and the second well region have a second conductivity type that is different from the first conductivity type,
• wherein a first PN junction of a first BJT device is formed between the first and second well regions, and a second PN junction of the first BJT device is formed between the second and third well regions;
• wherein the number of the first GAA field-effect transistors is greater than the number of the third GAA field-effect transistors, and the number of the third GAA field-effect transistors is greater than the number of the second GAA field-effect transistors.