Method for diffusing a conductivity determining impurity in a semiconductor substrate and making electrical contact thereto.

摘要

A method for diffusing a conductivity determining impurity in a semiconductor substrate and making electrical contact thereto by depositing a conductive layer (18) made of a rare earth hexaboride material containing a predetermined amount of silicon in it over a surface portion (14, 16) of substrate (10) and heating the substrate for a predetermined period of time at a predetermined temperature which is sufficient to cause boron from the hexaboride material to diffuse into the adjoining portion (20, 22) of substrate (10) to modify its conductor characteristics. At the same time a good electrical ohmic contact is established between the conductive layer and the adjoining substrate portion while the conductive layer retains its conductivity even after the outdiffusion of some of its boron into the substrate during the heat treatment. A silicon dioxide layer (19) is also formed on the exposed surface of the silicon containing hexaboride material through the oxidation of the silicon close to the exposed surfaces of the hexaboride material.