Improvement of electrical characteristics of polycrystalline silicon-contacted diodes after forward bias stressing

Improvement of the electrical characteristics of polycrystalline silicon (polysilicon) contacted n+-p diodes after application of a forward bias stressing is reported. The improvement existed for diodes whose emitter-implanted doses of arsenic were larger than 6×1015 cm−2 for HF-dipped devices, and 1×1016 cm−2 for H2SO4 heat-treated devices. The improvement is believed to be due to the neutralization by arsenic of dangling bonds at polysilicon grain boundaries and at the poly/mono silicon interfaces during the stressing process.