STI stress-induced increase in reverse bias junction capacitance

A new contribution to reverse-biased junction capacitance is reported. This component arises from trench isolation stress-induced bandgap narrowing that changes the built-in potential. Experimental junction capacitance measurements show good correlation to simulated oxidation stresses. The reported data agrees well with the predicted values from basic device equations. Stress induced capacitance increase of 12% (7.5%) at 3.3 V reverse bias for p/sup +//n (n/sup +// p) junctions, respectively is observed. In addition, well-understood reverse junction leakage relation to stress is also reported. This phenomenon will become increasingly important as trenches become shallower and more tightly spaced.