Method to Fabricate Resistors With Tight Sheet Rho
Original Publication Date: 1984-Feb-01
Included in the Prior Art Database: 2005-Feb-02
A method is described herein where multiple-sheet rho resistors can be fabricated with the same diffusion or ion implantation source. Contacts to resistors can be made with polysilicon to minimize the contact resistance. Further, as the sheet rho can be controlled by etching in dopants, the need to use different diffusion sources to obtain different sheet rho is eliminated. A specific example of such a process is as follows: After performing the conventional processes of growing an epitaxial layer 10 on a substrate device isolation, diffusion, etc., layers of silicon dioxide 12, P type polysilicon 14 and silicon dioxide 16 are deposited as shown in Fig. 1. The structure is covered with a resist layer and the resistor pattern is defined by conventional lithography and etching technique to form Fig. 2.