Process for Fabricating Submicron Resistors With the Base Polysilicon
Original Publication Date: 1988-Jan-01
Included in the Prior Art Database: 2005-Feb-14
Submicron resistors for semiconductors are formed by using base polysilicon (PolySi) for the sidewall formation. The proposed method requires less process steps than existing methods and also includes resistors in silicon with high-dimensional control. Using the sidewall image transfer technique, as shown in Fig. 1, a layer 1 of PolySi doped with boron is deposited over an oxide 2/nitride 3 layer laid down on an Si substrate 4. The oxide/nitride layer was defined using a reactive ion etch (RIE) of the nitride plus most of the oxide with a wet etch of the remaining SiO2 . The Si3N4 was introduced for applications where p+ PolySi is allowed to overlap the deep trench isolation. The dual-dielectric concept is known to prevent shorts between conducting layers. (Image Omitted) The PolySi of Fig.