Buried PIP capacitor for mixed-mode process

Abstract

A new method is provided for the creation of PIP capacitors for mixed-mode processes. The process starts with the creation of Shallow Trench Isolation regions in the surface of a substrate, defining active regions and the region over which the PIP capacitor is to be created on the surface of the substrate. The PIP STI region is etched, lowering the surface of the PIP STI region. A first layer of polysilicon is selectively deposited in the opening created in the layer of STI over which the PIP is to be created, the first layer of polysilicon is polished. The wells for the isolation of the gate electrode and the PIP STI region are implanted in the surface of the substrate. A layer of insulation, serving as the layer of dielectric for the capacitor, is blanket deposited over the surface of the substrate. The deposited layer of insulation is patterned and etched, leaving the layer of insulation in place overlying the first layer of polysilicon. The mixed-mode process is then resumed with conventional processing of creation of a layer of gate oxide, the deposition and patterning of a second layer of polysilicon and the additional Back-End-Of-Line (BEOL) processing that is required to complete the mixed mode structure of a PIP capacitor and a gate electrode.

Dependencies are inferred from the claim text.