A simple and accurate method to measure the threshold voltage of a MOSFET using an MOS active attenuator

An efficient method is developed to measure the threshold voltage of MOSFETs based on a simple MOS active attenuator, which requires only two MOSFETs. By measuring the terminal voltages of a MOS active attenuator under two different biases and through a simple calculation, the threshold voltage of a MOSFET in the active attenuator can be obtained accurately. The proposed scheme is very simple and can be implemented easily in the test keys of a wafer. Furthermore, the measuring/calculating procedure can be performed quite fast. Therefore, it is suitable for threshold voltage extraction, which is important in MOSFET characterization and process monitoring. HSPICE simulation results are given to verify the correctness and usefulness of this newly proposed scheme.