Process for making an integrated circuit with a damping resistor in combination with a buried decoupling capacitor

Abstract

Abstract An integrated circuit and process for making it wherein a decoupling capacitor is provided beneath devices in the surface of the integrated circuit by the formation of a first epitaxial layer between an N substrate having a P zone diffused therein and an N device-containing epitaxial layer. A P channel diffusion to the P zone formed in the substrate will serve as a damping resistor in combination with the coupling capacitor. The process for forming such a decoupling capacitor in an integrated circuit comprises, inter alia, diffusing P impurities into the substrate to form a large junction which will subsequently function as a decoupling capacitor. A first intrinsic, P or N epitaxial layer is then grown on the semiconductor substrate. Subsequently, an N epitaxial layer is grown on the first epitaxial layer. A P channel is then driven through the N epitaxial layer and the first epitaxial layer to contact the P diffused zone which serves as the decoupling capacitor. This P channel diffusion will serve as a damping resistor in combination with the decoupling capacitor. Device diffusion, i.e., transistors, resistors, etc., will take place into the N epitaxial layer, and during growth of the epitaxial layers the P zone will significantly outdiffuse into the first epitaxial layer. Appropriate channels, isolations and contacts are also provided.

Inventors

• 👤 C Chen
• 👤 V Dhaka
• 👤 W Krolikowski

Bibliographic Details