SEG/ELO material characterization using silicon bipolar transistors

In development of the epitaxial lateral overgrowth (ELO) bipolar transistor, devices were fabricated in silicon selective epitaxial growth (SEG). These devices were used to characterize electrically the quality of the SEG material. Three silicon bipolar transistors with almost identical doping profiles and geometries were simultaneously fabricated on the same wafer and their electrical characteristics compared. The three transistors were located in the substrate, a single SEG layer, and a double (interrupted growth) SEG layer. The SEG silicon was grown in a reduced pressure, RF-heated, pancake-type epitaxial reactor at 950°C and 150 torr. The transistors were tested for junction ideality factors, junction reverse bias leakage currents, and forward DC current gain. Test results showed average ideality factors, leakage currents, and gains were similar for all device types, indicating the excellent device quality of the SEG material relative to the substrate