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A set of equations of stress-mediated evolution of the nonequilibrium dopant-defect system in semiconductor crystals

Alexander K. Fedotov 2Oleg I. Velichko 1Vladimir A. Dobrushkin 3

1. Belarusian State University of Informatics and Radioelectronics (BSUIR), P.Brovka str. 6, Minsk 220000, Belarus
2. Belarusian State University (BSU), F. Skaryna av. 4, Minsk 220050, Belarus
3. Brown University, Providence, RI 02912, United States

Abstract

The principal trend in modern electronics is decrease in the dimensions of semiconductor devices and usage of diverse multilayer structures to achieve the required parameters of devices. It means that interfaces exert a significant effect on the evolution of dopant-defect system and hence on the electrophysical parameters of advanced electronic devices. This influence has a multifactor character, but changes in defect generation and annihilation due to elastic stresses in the vicinity of interface comes into particular prominence.
For analysis of the above-mentioned phenomena, a set of the equations for stress-mediated evolution of the nonequilibrium dopant-defect system is proposed. This set includes the equation of the dopant atoms diffusion in a field of elastic stress written for the two-stream diffusion mechanism by pairs dopant atom - self-interstitial and dopant atom - vacancy; continuity equation for the dopant atoms incorporated into clusters, diffusion equation of point defects under stress conditions written for interstitials and vacancies; continuity equation for the self-interstitials which are included in the clusters of dopant atoms and extended defects, expression for the built-in electric field strength distribution and expression for the effective drift velocities of dopant atoms, vacancies and self-interstitials in the field of elastic stress. Analysis of the system of equations obtained shows that it allows one to describe the most of features of doping processes investigated experimentally, such as the phenomena of uphill diffusion and the formation of a maximum of dopant concentration in the vicinity of interface during thermal treatments of ion-implanted layers as well as the effect of vacancy and self-interstitials separation. Using the formulated equations, we have investigated the processes of stress-mediated evolution of the nonequilibrium dopant-defect system and compared these calculations with experimental data.

 

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Related papers

Presentation: poster at E-MRS Fall Meeting 2003, Symposium B, by Alexander K. Fedotov
See On-line Journal of E-MRS Fall Meeting 2003

Submitted: 2003-04-30 16:43
Revised:   2009-06-08 12:55