Method of Contacting Shallow Emitters
Original Publication Date: 1981-Feb-01
Included in the Prior Art Database: 2005-Feb-10
Metallizing very shallow emitters of bipolar transistors has proven difficult, since device degradation occurs when platinum (Pt) is sintered to form the PtSi ohmic contacts. This is believed to be due to excessive penetration by the PtSi formed especially at the emitter perimeter where the lateral diffusion is less than the vertical junction depth. Also, there is an extended layer of Pt over the adjacent insulator during sintering so that greater penetration occurs at the emitter edge in order to satisfy the solubility of the additional overlying Pt within a diffusion length or two.