Reproducibility of Phosphorus and Arsenic Doped Polysilicon Emitters

In order to improve the reproducibility of current gain and emitter efficiency of polysilicon emitter transistors, polysilicon deposition was carried out in the Advance 600/2 clustertool provided with in-situ HF vapour clean and controlled oxidation step and compared with a conventional polysilicon furnace. However, for both types of furnaces, batch to batch non-uniformity for phosphorus doped emitters was unacceptably high (≫ 100%), whereas RTA annealed arsenic doped emitters show good reproducibility (≪ 50%) in Gumel emitter number.