Operation of functional circuit elements using BEOL-transistor with InGaZnO channel for on-chip high/low voltage bridging I/Os and high-current switches

Functional circuit elements based on novel BEOL-transistors with a wide-band-gap oxide semiconductor InGaZnO (IGZO) film are integrated onto LSI Cu-interconnects, and their operations are demonstrated. High-current comb-type transistors show excellent I_on/I_off ratio (>;10⁸) and high-V_d operation with linear area dependence, realizing area-saving compact high-current BEOL switches. Successful operation of voltage-controlled inverter switches with high-V_d enables on-chip bridging I/Os between high/low voltage on conventional Si system LSIs. Setting the gate-to-drain offset design to just 0.1μm realizes +20V enhancement of the breakdown voltage to ~60V with excellent safety operation at around V_d=50V due to the wide-band-gap characteristics.