Method Of Making Isolation Contact To Integrated Circuit Substrate
Original Publication Date: 1979-Apr-01
Included in the Prior Art Database: 2005-Feb-20
Polysilicon contact is made to the substrate of a deep dielectrically isolated integrated circuit chip using the following high performance polysilicon device process. 1. N+ subcollector 1 is placed in P- substrate 2. 2. N epi (epitaxial layer) 3 is grown over the substrate to y ield Fig. 1. 3. Shallow trench 4 and deep trench 5 are formed in separate steps using reactive ion etching to yield Fig. 2. 4. Thermal oxide is grown (not shown) to mask all but the dee p trench 5; boron 6 is implanted. 5. Shallow trench 4 and deep trench 5 are filled with pyro oxide and planarized to yield Fig. 3. 6. P base implant 7 and N+ reach-through implant 8 are made. 7. Any remaining oxide is removed, 300 angstroms oxide 9 is g rown, and 300 angstroms Si(3)N(4) 10 is deposited to yield Fig. 4. 8.