Formation of lateral thin-film 700-V insulated-gate bipolar transistors by using retrograde p-well double implantation scheme

Formation of lateral thin-film 700-V insulated-gate bipolar transistors (IGBTs) on Si-semiconductor-on-insulator (Si-SOI) substrates by using retrograde p-well double implantation scheme has been proposed. With a low thermal budget for p-well formation, retrograde high-energy boron implantation is employed to cause a high dopant concentration in the bulk region, and additional low-energy boron implantation is carried out for alleviating the surface punch-through of MOSFET (metal-oxide-semiconductor-field-effect-transistor) structure. As compared to the conventional p-well formation process, the retrograde double implantation scheme can lead to better latchup immunity, due to a considerably higher dopant concentration and thus lower well resistance in the p-well bulk region. In addition, owing to a lower surface dopant concentration, the retrograde double implantation scheme can lead to better on-state characteristics than the conventional process, while achieving comparable blocking voltage.