Ohmic Contacts to Semiconductor Devices Using Barrier Layers of Aluminum and Titanium
Original Publication Date: 1985-Sep-01
Included in the Prior Art Database: 2005-Feb-19
This aluminum-based metallurgy technique provides ohmic contacts to both n- and p-type silicon and incorporates ohmic barrier metal layers of aluminum for p-type contacts and a refractory metal for n-type contacts. Evaporated metals are defined by sequential lift-off deposition steps. Fig. 1 shows a partially processed metal-oxide semiconductor (MOS) device including p-type substrate 10 having recessed oxide isolation 12 on its surface. Contact holes 14, 16 and 18 are to be provided for a metal interconnect layer, not shown in Fig. 1. The following process steps can be used to etch the desired vias and form the contact metallurgy.