High-voltage complementary BEOL-FETs on Cu interconnects using N-type IGZO and P-type SnO dual oxide semiconductor channels

A BEOL-process-compatible, high-voltage complementary MISFET inverter formed on Si-LSI Cu-interconnects (hereafter we call BEOL-CMOS), is presented for the first time. High I
_on
/I
_off
ratio N-type IGZO and P-type SnO dual oxide semiconductor channels are integrated to form BEOL-CMOS logic with just two mask addition to the state-of-the-art BEOL process. BEOL-CMOS flow is developed from the NFET and PFET unipolar technologies, resolving several integration issues. The high-V
_DD
inverters enable low-V
_in
/high-V
_out
and high-V
_in
/low-V
_out
interactive operation (V
_in
: up to 20V, V
_out
: 0.9~5V). This BEOL-CMOS technology is a strong candidate to realize low-power voltage-bridging I/Os, which gives standard LSIs a special add-on function for smart society applications.