A structure for picking up a collector region including a pair of polysilicon stacks formed in the isolation regions and extending below the collector region; and a pair of collector electrodes contacting on the polysilicon stacks, wherein the pair of polysilicon stacks includes: an undoped polysilicon layer and a doped polysilicon layer located on the undoped polysilicon layer, wherein a depth of the doped polysilicon layer is greater than a depth of the collector region; the depth of the collector region is greater than a depth of the isolation regions.