A Single MOSFET-Based Oscillator on a Bulk-Silicon Wafer

A large kink, causing an abrupt transition of drain current (I-DS) from a low to a high level, is observed even in a MOSFET on a bulk-silicon wafer (bulk-MOSFET). When a constant input current (I-in) is applied to the drain (D) of a bulk-MOSFET, an oscillating output voltage (Vout) is generated from the same D similar to the oscillation that occurs in a MOSFET on a silicon-on-insulator (SOI) wafer. This characteristic is attributed to the floating body (FB) effect. In the same manner that a physical FB usually exists in a SOI-device, an electrical FB is realized even in a bulk-device due to the built-in potential between a moderately doped p-well and an underlying lightly doped p-type wafer. This bulk-MOSFET oscillator can be utilized in biomedical and neuromorphic applications.