US Patent 10249769 On-chip tuneable diffusion resistor

An object of the disclosure is to take a CMOS varactor structure (NMOS in N-well or PMOS in P-well) and turn it in to a three terminal on-chip tuneable diffusion resistor. The diffusion resistor can be made with an n+ diffusion inside the p-substrate, or with a p+ diffusion inside an N-well that lies within the p-substrate. The resistor can be implemented in any existing CMOS or BICMOS silicon technology, without using additional masks. The resistor can be also implemented in a technology with FINFETs.