Highly-stable four-point-probe metrology in implant and epitaxy processes

The resistivity (doping level) in epitaxial and implant layers has high impact on electrical device parameters of power semiconductors. However, precise control of electrical layer resistivity with the four-point-probe (4PP) technique is still challenging due to the contact between semiconductor layers with metal probes. In this work, the repeatability of 4PP sheet resistance (Rs) measurement on epitaxial and implant layers was studied. The results prove the excellent repeatability and reliability of sheet resistance metrology on the power semiconductor processing layers.