| abstract |
A semiconductor device structure is provided. The semiconductor device structure includes a substrate having a top surface. The semiconductor device structure includes a first pillar structure over the substrate. The first pillar structure includes a first heavily n-doped layer, a first p-doped layer, an n-doped layer, and a first heavily p-doped layer, which are sequentially stacked together. The first pillar structure extends in a direction away from the substrate. |