In situ-doped amorphous Si/sub 0.8/C/sub 0.2/ emitter bipolar transistors

The fabrication and characterization of in situ-doped amorphous Si/sub 0.8/C/sub 0.2/ emitter transistors are presented. Emitter Gummel numbers exceeding 10/sup 14/ s/cm/sup 4/ are reported for the first time in this type of structure. The high values obtained for G/sub E/ are believed to be due to the valance band discontinuity between the Si/sub 0.8/C/sub 0.2/ layer and the crystalline part of the emitter, which effectively blocks the minority carrier injection from the base into the noncrystalline part of the emitter.