Abstract: The present disclosure provides a testkey structure and a monitoring method with a testkey structure, and the testkey structure includes a first diffusion region and a second diffusion region, a first gate and a second gate, a first epitaxial layer and a second epitaxial layer, and an input pad and an output pad. The first diffusion region and the second diffusion region are disposed in a substrate. The first gate and the second gate are disposed on a substrate, across the first diffusion region and the second diffusion region respectively. The first epitaxial layer and the second epitaxial layer are respectively disposed on the second diffusion region and the first diffusion region, separately disposed between the first gate and the second gate. The input pad and the output pad are electrically connected to the first epitaxial layer and the second epitaxial layer respectively.

Abstract: The invention provides a semiconductor testkey, which comprises a testkey on a substrate, the testkey comprises a first resistor pattern, a second resistor pattern and a third resistor pattern arranged in a strip, the distance between the first resistor pattern and the second resistor pattern is defined as a first distance, and the distance between the second resistor pattern and the third resistor pattern is defined as a second distance, the first resistor pattern, the second resistor pattern and the third resistor pattern have the same pattern, and the second distance is larger than the first distance.