Dense Trench-Isolated Substrate Contact
Original Publication Date: 1985-Nov-01
Included in the Prior Art Database: 2005-Feb-19
A process is provided for making small dimension substrate contacts by using trench isolation techniques which results in a novel substrate contact structure. In this process, a region of a metal layer is formed in an empty trench in contact with a semiconductor substrate and an N+ diffusion region such as a subcollector region which is contacted by a reach-through region extending from the upper surface of the structure. As indicated in the figure, a contact trench 10 is formed through an N+ reach-through region 12 and an N+ subcollector region 14 into a P type semiconductor substrate 16. Reach-through region 12 is located in an N type epitaxial layer 18 grown on substrate 16, and subcollector region 14 is located along the interface between N type epitaxial layer 18 and P type substrate 16.