RELATIONSHIP BETWEEN STRESS AND DANGLING BOND GENERATION AT THE (111)SI/SIO2 INTERFACE

Electron spin resonance analysis of the intrinsic density [P(b)] of interfacial P(b) (.Si=Si3) defects in thermal (111)Si/SiO2 as a function of oxidation temperature T(ox) in the range 200-1140-degrees-C reveals a close linear correlation with the average stress sigma(av) in the superficial SiO2 layer. An almost constant high value [P(b)] is similar to 1 x 10(13) cm-2 is found for T(ox) less-than-or-equal-to 800-degrees-C, while from this T(ox) onward, [P(b)] decreases monotonically to < 10(10) cm-2 along with sigma(av) --> 0 for T(ox) --> 1150-degrees-C. The underlying effect is cooperative structural relaxation of the SiO2 layer initiating at approximately 800-degrees-C, thus gradually eliminating the need for P(b) formation to account for lattice mismatch.