Integration of germanium photo detector in CMOS processing

摘要

A method and device are provided for forming an integrated Ge or Ge/Si photo detector in the CMOS process by non-selective epitaxial growth of the Ge or Ge/Si. Embodiments include forming an N-well in a Si substrate; forming a transistor or resistor in the Si substrate; forming an ILD over the Si substrate and the transistor or resistor; forming a Si-based dielectric layer on the ILD; forming a poly-Si or a-Si layer on the Si-based dielectric layer; forming a trench in the poly-Si or a-Si layer, the Si-based dielectric layer, the ILD, and the N-well; forming Ge or Ge/Si in the trench; and removing the Ge or Ge/Si, the poly-Si or a-Si layer, and the Si-based dielectric layer down to an upper surface of the ILD. Further aspects include forming an in-situ doped Si cap epilayer or an ex-situ doped poly-Si or a-Si cap layer on the Ge or Ge/Si.