Superconducting Ohmic Contact
Original Publication Date: 1989-Nov-01
Included in the Prior Art Database: 2005-Jan-29
Ohmic contacts constitute a major issue in the performance of high- speed integrated circuits. This is in fact more so in bipolar technology where high current densities are used. Present ohmic contact technology uses tunneling ohmic contacts which result when very high doping levels are employed at the metal/silicon interface. The contact resistance is very sensitive to the doping level at the silicon surface, and is a major detractor from circuit performance. The problem exacerbates at low temperatures due to possible carrier freeze-out. As devices scale, the problem is made severe because of the low-temperature processing employed, which in many cases does not fully activate the dopant in the silicon. Furthermore, when deep donors or acceptors are used (such as Ga, In, etc.) good ohmic contacts are almost impossible.