OBSERVATION AND ELECTRONIC CHARACTERIZATION OF NEW E' CENTER DEFECTS IN TECHNOLOGICALLY RELEVANT THERMAL SIO(2) ON SI - AN ADDITIONAL COMPLEXITY IN OXIDE CHARGE TRAPPING

Using electron-spin resonance (ESR), we demonstrate that several E' va riant precursors exist in a variety of technologically significant the rmally grown thin SiO2 films on Si. The E' variants include two variet ies with the ubiquitous E(gamma)' line shape (zero-crossing g = 2.0005 , O3 = Si.) and a second very narrow line shape (zero-crossing g = 2.0 019, structure unknown). We tentatively label the g = 2.0019 defect EP for provisional E' and distinguish the E(gamma)' variants E(gamman)' (neutral) and E(gammap)' (positive). We combine ESR, capacitance versu s voltage electrical measurements, and charge injection sequences to c ompare the electronic properties of the defects. We find that paramagn etic EP defects are positively charged while paramagnetic E(gamma)' ce nters can be either positively charged or, under some circumstances, n eutral. We find that EP precursors have a very large capture cross sec tion for holes (sigma = 10(-13) cm2) and that paramagnetic EP defects have an even larger capture cross section for electrons (sigma = 10(-1 2) cm2). Both EP capture cross sections are an order of magnitude grea ter than those of the E(gammap) defects. We find that EP centers are d istributed much more broadly throughout the oxide than either the E(ga mmap)' or E(gamman)' defects. We also find a two order of magnitude va riation in EP density dependent upon processing variations. In additio n, EP centers, unlike the E(gamma)' variations, are not stable at room temperature. With their large capture cross section for holes and eve n larger capture cross section for electrons, EP defects may be releva nt to device reliability and charge trapping under conditions of a low , relatively pure hole fluence such as in hot hole injection in short n-channel metal-oxide-semiconductor field-effect transistors.