Dynamic Behavior of Intrinsic Point Defects in Fz and Cz Silicon Crystals

1992 ◽  
Vol 262 ◽  
Author(s):  
Takao Abe ◽  
Hiroshi Takeno

ABSTRACTDetaching the crystals from the melt revealed the real state and dynamic change of intrinsic point defects. From this observation it is confirmed that the predominant point defects near the melting point are vacancies. Clusters of interstitial-type dislocation loops (CDL) are eliminated by taking an extremely low growth rate under 0.2 mm/min and nitrogen doping. The anomalous oxygen precipitate (AOP) of the crystals grown in a nitrogen ambient is enhanced. AOP and ring-oxidation induced stacking fault (R-OSF) coexist at the periphery in nitrogen doped crystals. Almost all crystals have defect boundaries between periphery and center region which may be attributed to a stress field in the crystals during growth.

2011 ◽  
Vol 178-179 ◽  
pp. 3-14 ◽  
Author(s):  
Vladimir V. Voronkov ◽  
Robert Falster

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.


Author(s):  
Byung-Teak Lee

Grown-in dislocations in GaAs have been a major obstacle in utilizing this material for the potential electronic devices. Although it has been proposed in many reports that supersaturation of point defects can generate dislocation loops in growing crystals and can be a main formation mechanism of grown-in dislocations, there are very few reports on either the observation or the structural analysis of the stoichiometry-generated loops. In this work, dislocation loops in an arsenic-rich GaAs crystal have been studied by transmission electron microscopy.The single crystal with high arsenic concentration was grown using the Horizontal Bridgman method. The arsenic source temperature during the crystal growth was about 630°C whereas 617±1°C is normally believed to be optimum one to grow a stoichiometric compound. Samples with various orientations were prepared either by chemical thinning or ion milling and examined in both a JEOL JEM 200CX and a Siemens Elmiskop 102.


Author(s):  
L. J. Sykes ◽  
J. J. Hren

In electron microscope studies of crystalline solids there is a broad class of very small objects which are imaged primarily by strain contrast. Typical examples include: dislocation loops, precipitates, stacking fault tetrahedra and voids. Such objects are very difficult to identify and measure because of the sensitivity of their image to a host of variables and a similarity in their images. A number of attempts have been made to publish contrast rules to help the microscopist sort out certain subclasses of such defects. For example, Ashby and Brown (1963) described semi-quantitative rules to understand small precipitates. Eyre et al. (1979) published a catalog of images for BCC dislocation loops. Katerbau (1976) described an analytical expression to help understand contrast from small defects. There are other publications as well.


Author(s):  
Haixi Pan ◽  
Liping Feng ◽  
Xiaodong Zhang ◽  
Yang Chen ◽  
Gangquan Li ◽  
...  

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