Two-dimensional model of the intrinsic point defects behavior during Cz silicon crystal growth

2001 ◽  
Author(s):  
Anatolii I. Prostomolotov ◽  
Natalia A. Verezub
Keyword(s):  
Crystal Growth ◽  
Point Defects ◽  
Silicon Crystal ◽  
Two Dimensional ◽  
Dimensional Model ◽  
Intrinsic Point Defects ◽  
Two Dimensional Model

Intrinsic Point Defects in Silicon Crystal Growth

2011 ◽  
Vol 178-179 ◽  
pp. 3-14 ◽  
Author(s):  
Vladimir V. Voronkov ◽  
Robert Falster
Keyword(s):  
Crystal Growth ◽  
Point Defects ◽  
Vacancy Concentration ◽  
Silicon Crystal ◽  
Growth Conditions ◽  
Intrinsic Point Defects ◽  
Silicon Crystals ◽  
Low Concentrations ◽  
Different Populations ◽  
Vacancy Concentrations

In dislocation-free silicon, intrinsic point defects – either vacancies or self-interstitials, depending on the growth conditions - are incorporated into a growing crystal. Their incorporated concentration is relatively low (normally, less than 1014 cm-3 - much lower than the concentration of impurities). In spite of this, they play a crucial role in the control of the structural properties of silicon materials. Modern silicon crystals are grown mostly in the vacancy mode and contain many vacancy-based agglomerates. At typical grown-in vacancy concentrations the dominant agglomerates are voids, while at lower vacancy concentrations there are different populations of joint vacancy-oxygen agglomerates (oxide plates). Larger plates – formed in a narrow range of vacancy concentration and accordingly residing in a narrow spatial band – are responsible for the formation of stacking fault rings in oxidized wafers. Using advanced crystal growth techniques, whole crystals can be grown at such low concentrations of vacancies or self-interstitials such that they can be considered as perfect.

Commitment to pro- versus counter-attitudinal behavior and the dynamics of social representations

2002 ◽  
Vol 61 (1) ◽  
pp. 34-44 ◽  
Author(s):  
Eric Tafani ◽  
Lionel Souchet
Keyword(s):  
Higher Education ◽  
Social Representations ◽  
Cognitive Restructuring ◽  
Social Representation ◽  
Two Dimensional ◽  
Dimensional Model ◽  
Social Actions ◽  
The Social ◽  
Two Dimensional Model ◽  
Students Attitudes

This research uses the counter-attitudinal essay paradigm ( Janis & King, 1954 ) to test the effects of social actions on social representations. Thus, students wrote either a pro- or a counter-attitudinal essay on Higher Education. Three forms of counter-attitudinal essays were manipulated countering respectively a) students’ attitudes towards higher education; b) peripheral beliefs or c) central beliefs associated with this representation object. After writing the essay, students expressed their attitudes towards higher education and evaluated different beliefs associated with it. The structural status of these beliefs was also assessed by a “calling into question” test ( Flament, 1994a ). Results show that behavior challenging either an attitude or peripheral beliefs induces a rationalization process, giving rise to minor modifications of the representational field. These modifications are only on the social evaluative dimension of the social representation. On the other hand, when the behavior challenges central beliefs, the same rationalization process induces a cognitive restructuring of the representational field, i.e., a structural change in the representation. These results and their implications for the experimental study of representational dynamics are discussed with regard to the two-dimensional model of social representations ( Moliner, 1994 ) and rationalization theory ( Beauvois & Joule, 1996 ).

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