Grain size modulation on impurity doped polysilicon by implant and rapid thermal process tuning and its influence on sheet resistance

Polycrystalline silicon has attracted our interest for their applications. Its electrical characteristics are closely correlated to the crystalline structure after electrical activation. The parameters related to crystalline structure are strongly influenced by implant and annealing techniques. We investigate the influence and sensitivity of implant / annealing / microstructure / mobility on sheet resistance (Rs) of doped polysilicon film, which is prepared by a CVD reactor and implanted by various germanium and boron conditions. We also combine with RTP/LSA sequences to active and recrystallize polysilicon. Finally, fitting results of XRD is used to calculate grain size which shows strong correlation with Rs. We study on using implant/annealing process to modulate polysilicon Rs and its grain size. Different dopant species and annealing techniques were discussed its influence on these parameters. Data shows that Rs is inverse on grain size and it can be adjusted by process conditions to meet device requirement.