Abstract: An improved Schottky transistor structure (6), including a bipolar transistor structure (7) and a Schottky diode structure (8), is formed by retrograde diffusing relatively fast diffusing atoms to form a localized retrograde diode well (9) as the substrate for the Schottky diode structure. An expanded buried collector layer (11) formed of relatively slow diffusing atoms underlies the base and collector regions of the bipolar transistor structure (7) and the retrograde diode well (9). A diode junction (10) is formed by expanding the base contact of the bipolar transistor structure to include the surface of the retrograde diode well. Preferably, the diode junction is a Platinum-Silicide junction.

Abstract: A lateral PNP transistor structure is fabricated in a BICMOS process utilizing the same steps as are used during the BICMOS process for fabricating NPN and CMOS transistors without requiring additional steps. A base N+ buried layer B/N+BL formed in the IC substrate P/SUB underlies the bipolar PNP transistor. A base Retro NWELL B/NWELL and a base contact Retro NWELL BC/NWELL are formed in the base N+ buried layer B/N+BL using the CMOS Retro NWELL mask, etch and N type introduction sequence. An epitaxial layer EPI of undoped or low doped EPI is deposited across the IC substrate and isolation oxide regions ISOX isolating the PNP transistor are grown during the isolation oxide ISOX mask, etch and grow sequence. The NPN collector sink definition mask, etch and N type introduction sequence is used to form a PNP base contact N+ sink region BC/N+SINK to the BC/NWELL and B/N+BL.

Abstract: An improved Schottky diode structure (4) is formed by retrograde diffusing an N.sup.+ concentration of relatively fast diffusing atoms, preferably Phosphorus atoms, to form a localized diode NWell (6) as the diode substrate for the diode. A buried diode layer (5) formed of relatively slow diffusing N type atoms, preferably Antimony atoms, underlies the diode NWell and electrically couples the diode junction (7) to the diode ohmic contact (9). A diode ohmic contact region (31) underlies the ohmic contact, further coupling the diode junction to the ohmic contact. Preferably, the diode junction is a Platinum-Silicide junction.

Abstract: An improved Schottky diode structure (4) is formed by retrograde diffusing an N.sup.+ concentration of relatively fast diffusing atoms, preferably Phosphorus atoms, to form a localized diode NWell (6) as the diode substrate for the diode. A buried diode layer (5) formed of relatively slow diffusing N type atoms, preferably Antimony atoms, underlies the diode NWell and electrically couples the diode junction (7) to the diode ohmic contact (9). A diode ohmic contact region (31) underlies the ohmic contact, further coupling the diode junction to the ohmic contact. Preferably, the diode junction is a Platinum-Silicide junction.