Using Aluminosilicate for Deep Trench Isolation
Original Publication Date: 1980-Aug-01
Included in the Prior Art Database: 2005-Feb-13
Deep dielectric isolation is formed by reactive ion etching trenches or grooves in monocrystalline silicon substrate and then filling the trenches with insulators, such as silicon dioxide (SiO(2)). When a deep trench is filled with SiO(2) for isolation, the mismatch of thermal expansion coefficient between silicon and SiO(2) could be a potential problem for cavity formation, swelling in the filled region, and defect formation in the silicon around the trench area during various thermal cycles of subsequent processing. The linear thermal expansion coefficients for SiO(2), Si and Al(2)O(3) are given in the figure. If the following assumptions are made: 1. thermal expansion coefficient alpha of Si (poly) approximates alpha of Si (single crystal), 2.