Semiconductor device structure and methods of forming the same are described. The structure includes a first dielectric layer including a first portion disposed over a source/drain region in an active region of a substrate and a modulation portion over an interlayer dielectric (ILD) in a resistor region of the substrate, the first portion of the first dielectric layer has a first composition, and the modulation portion of the first dielectric layer has a second composition different from the first composition. The structure further includes a resistor layer disposed on the modulation portion of the first dielectric layer in the resistor region and a second dielectric layer disposed over the first dielectric layer in the active region and over the resistor layer in the resistor region.