The structure for millimeter-wave frequency applications, includes a Schottky barrier diode (SBD) with a cutoff frequency (FC) above 1.0 THz formed on a SiGe BiCMOS wafer. A method is also contemplated for forming a Schottky barrier diode on a SiGe BiCMOS wafer, including forming a structure which provides a cutoff frequency (Fc) above about 1.0 THz. In embodiments, the structure which provides a cutoff frequency (Fc) above about 1.0 THz may include an anode having an anode area which provides a cutoff frequency (FC) above about 1.0 THz, an n-epitaxial layer having a thickness which provides a cutoff frequency (FC) above about 1.0 THz, a p-type guardring at an energy and dosage which provides a cutoff frequency (FC) above about 1.0 THz, the p-type guardring having a dimension which provides a cutoff frequency (FC) above about 1.0 THz, and a well tailor with an n-type dopant which provides a cutoff frequency (FC) above about 1.0 THz.