Shallow‐emitter, narrow‐basenpnbipolar transistor structures have been obtained by implantation of B+and As+ions into amorphous Si layers formed by the prior implantation of Si+ions. Thermal annealing results in recrystallization of the amorphous layers by solid phase epitaxy and activation of the implanted dopant atoms. Emitter‐base junction depths and base widths of ∼0.10 &mgr;m, as determined by secondary ion mass spectroscopy analysis, have been achieved both for single‐crystal Si samples and for samples with poly‐Si emitter contacts. Transmission electron microscopy shows that the recrystallized layers are almost free of defects near the emitter‐base and base‐collector junctions. Discrete bipolar transistors with good electrical characteristics have been fabricated using this technique.