Oxygen, Oxidation Stacking Faults, and Related Phenomena in Silicon
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and Tan, eds.
333
Defects in Semiconductors
OXYGEN,
OXIDATION STACKING FAULTS, AND RELATED PHENOMENA IN SILICON
S. M. HU IBM General Technology Division, East Fishkill, Hopewell Junction, USA
NY 12533,
ABSTRACT Some salient features of the phenomena of oxidation stacking faults (OSF) and oxidation enhanced diffusion (OED) are summarized, and some theories of OSF growth are Then a new theory is developed which shows critiqued. the growth to be reaction controlled, and the retrogrowth to be naturally a regime in the entire OSF growth process. The theory has provided an estimated bound on the activaIt is shown tion energy of self-diffusion in silicon. that the observed power law growth kinetics can be explained quite naturally by a bimolecular annihilation A possible process of the excess self-interstitials. physical model of such an annihilation process is discussed. A number of phenomena related to the nucleation of oxygen Then a model of precipitates in silicon are reported. nucleation is presented which is shown to be consistent In this model, the homogenwith all observed phenomena. eous nucleation proceeds not merely via the agglomeration of oxygen atoms, but in combination with small vacancy clusters. Evidence from the OSF and OED phenomena, and the nucleation of oxygen precipitates thus necessitates the dualism of vacancies and interstitials as thermal defects in silicon at high temperatures.
INTRODUCTION The study of oxidation stacking faults (OSF) in silicon has been largely motivated by the recognition of the role of such faults in the defect-limited Just as importantly, the study yield of silicon microelectronic circuits. has contributed to the understanding of basic aspects of point defects and This follows from the recognition that the phenomenon diffusion in silicon. of oxidation enhanced diffusion (OED) and that of OSF are different manifestations of nonequilibrium point defects in consequence of thermal oxidation [1, 2]. Due to extensive investigations over the past several years, a considerable body of information has now been accumulated on the phenomena of A number of theories have been OSF and OED; this will be briefly summarized. We proposed for the growth of OSF [2-5]; these will be briefly discussed. will then develop a new theory of OSF growth, in a very general and natural way, so that the observed power-law kinetics [6-8] has a very reasonable explanation, and the retrogrowth phenomenon [6-8] simply emerges as one regime of the entire OSF growth process. The topic of oxygen precipitation in silicon has been studied particularly Nonetheless, the aspect of nucleation intensively in the last several years. understood. We will report some of oxygen precipitates has remained little phenomena of the nucleation of oxygen precipitates, and then propose a model of nucleation that is consistent with all these and previously observed
334 phenomena. The acceptance both of the model of the nucleation of oxygen precipitates, and the model of OSF and OED, leads us to a dualism of the vacancy and t
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