Improving corrosion-resistance of polysilicon using boron doping and self-induced galvanic bias

In this paper we report upon two novel methods for improving the corrosion resistance of silicon-glass micropackages in high temperature saline soak tests. By using boron doping and/or galvanic biasing, we have shown that the dissolution of polysilicon can be reduced from more that 1 (mu)m /day to less than 90 A/day. Physical mechanisms for polysilicon corrosion are also presented. Further tests on the packages in-vitro show that the package maintains long-term hermeticity while soaking in high temperature saline.