Nanoscale wet etching of physical-vapor-deposited titanium nitride and its application to sub-30-nm-gate-length fin-type double-gate metal-oxide- semiconductor field-effect transistor fabrication

The nanoscale wet etching of physical-vapor-deposited (PVD) titanium nitride (TiN) and its application to sub-30-nm-gate-length fin-type doublegate metal-oxide-semiconductor field-effect transistor (FinFET) fabrication are systematically investigated. It is experimentally found that PVDTiN side-etching depth can be controlled to be one-half of PVD-TiN thickness with precise time control using an ammonium hydroxide (NH₄OH) : hydrogen peroxide (H₂O₂) : deionized water (H₂O) = 1 : 2 : 5 solution at 60 °C. Using the developed nanoscale PVD-TiN wet etching technique, sub-30-nm-physical-gate-length FinFETs, 100-nm-tall fin-channel complementary MOS (CMOS) inverters and static random access memory (SRAM) half-cells have successfully been fabricated and demonstrated. These experimental results indicate that the developed nanoscale PVDTiN wet etching technique is very useful for tall fin-channel CMOS fabrication.