Modeling microdefects formation in crystalline silicon : the roles of point defects and oxygen

Most microelectronic devices are fabricated on single crystalline silicon substrates that are grown from the melt by the Czochralski crystal growth method. There is an ever increasing demand for control of size and density of microdefects in the silicon for control of quality and uniformity of the fabricated microelectronic devices. This thesis is aimed at developing a fundamental understanding of the mechanisms for formation of such microdefects through the development of models, theoretical analysis and large-scale simulation. Two major problems have been addressed. First, following the work of T. Sinno [150] and T. Mori [108], models have been developed for the transport, reaction and aggregation of native point defects - self-interstitials ('s) and vacancies (V's) - in crystalline silicon, so as to explain the dynamics of void formation (aggregation of V's) and stacking faults (aggregation of I's). Second, the model of point defect and cluster dynamics has been extended to include oxygen, the most common impurity in silicon, and to model oxide precipitation, an important step in silicon wafer preparation and device processing. The models of microdefect formation begin with transport equations for native point defects that include transport by diffusion and convection (crystal motion), recombination of Is and Vs, and the loss of point defects to clusters. Cluster formation is modeled by a combination of discrete rate equations for small-sized clusters (less than 100) and continuous Fokker-Planck equations for large cluster sizes. Simulation methods are developed for calculating, in time, space and cluster size, the evolution of point defect and cluster profiles, as a function of the temperature distribution in the crystal.

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Chemical Engineering.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2003

Author dc:creator

• Wang, Zhihong, 1972-

Advisor dc:contributor.advisor

• Robert A. Brown.

• Chemical Engineering.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/16905

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/16905