Fabrication of Substrate Contacts
Original Publication Date: 1980-Jun-01
Included in the Prior Art Database: 2005-Feb-13
Starting with the silicon substrate 10, a silicon dioxide layer 11 is formed on the substrate's surface and lithographically masked such that the oxide layer 11 remains in the areas only where substrate contacts are desired. The exposed silicon is etched to a depth equivalent to the epitaxy that will be deposited later. This is followed by the normal blanket subcollector diffusion and drive-in to form N+ regions 12. The drive-in silicon dioxide layer 13, shown in Fig. 1, is removed by dip etching so that a residual oxide 11 remains on the substrate contact areas only.