Defects reduction

There are several approaches for dislocation density reduction [35]. It was shown [36, 37, 38] that the number of dislocations decreases with layer thickness, which results from dislocation reactions. The experimental behavior of dislocation density versus layer thickness h was found to be proportional to 1/h , where n = 0.66 [39]. This means that to obtain dislocation density in GaN in the mid 10 cm , the thickness of the layer should be in submillimeter range. However, cracking can appear in thick layers due to difference in thermal expansion coefficients between the substrate and the layer. Experimental [40] and theoretical calculations [41] show that screw and edge TDs in GaN are parallel to the [0001] direction and only mixed type 

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K. Ohtani, K. Ihara and T. Ohmi, Proceedings Electrochemical Society (Contamination, Control and Defect Reduction in Semiconductor Manufacturing) 92 (2), 361-74 (1992). 

Y. Gotkis, Post-CMP Surface Defectivity Classification, Origin, and Defect Reduction, IPEC Planar PACRIM Chemical Mechanical Planarization Symposium, Hsin Chu, Taiwan Sept. 30-Oct. 1, 1997. 

Capitanio et al, Defect Reduction During Chemical Mechanical Planarization by Incorporation of Slurry Filtration, Proceedings of SEMICONlWest Contamination in Liquid Chemical Distribution Systems Workshop (July 1998). 

Most structural materials are susceptible to a wide range of defects. Any flaw alters the behavior of a structure, even if only minutely. The larger the flaw the more it reduces the useful properties of the material. One of the challenges in modem materials engineering is defect reduction. Defect reduction involves defect detection, defect source determination and mechanisms and defect elimination. There is no single method of detect review that can fully characterize every defect each defect classification method has its own strengths. 

Vasilopoulos G, Lin Z, Johl B, Joshi S, Chatterjee B. Copper CMP defect reduction using POU filtration. Proceedings of CMP Technology for ULSI Intercon. Semicon West 2000 Jul San Francisco, CA. 

A rule two violation is when the process operates above or below its average performance for an extended period of time, specifically for nine or more consecutive measurement cycles. When this happens, investigating the causes could lead to permanent process improvement and defect reduction, even when the process has shifted in a favorable manner. 

Birnie, D.P., III, Kaz, D.M., and Taylor, D.J., Surface tension evolution during early stages of drying and correlation with defect reduction during spin-on of sol-gel coatings. Unpublished results. 

Wafer defect reduction PS layer as impurity getting center 233... 

Geanne, V. Lin, Z. Budge, J. Somit, J. Basab, C. Copper CMP Defect Reduction Using POU Filtration Semicon West Technical Program, Jul 2000. 

Figure 5.2 Schematic illustration of two defect reduction mechanisms for a strained film (dark gray) grown on a porous substrate (light gray), (a) Dislocations bending toward the open surface at the tube walls, (b) Formation of relatively dislocation-free regions in the GaN film where the film has laterally grown over the pores. Reproduced from C. K. Inoki etal., Pbys. Stat. Soli, (a) 200, 44. Copyright (2003), with permission from John Wiley Sons, Ltd...

For further evaluation of the material quality, dovetailed with the effect of SiNx network on the point defect reduction, time-resolved... 

Typical room temperature current-voltage (Z-V) characteristics of Ni/Au SDs are plotted in Figure 6.13. As we can see, the saturation current decreases monotonously with increasing SiN.r deposition time from 0 (the control sample) to 5 min which means that the effective Schottky barrier height increased owing to shallow defect reduction. Meanwhile, the series resistance and ideality factor also decreased when longer SiN deposition times were used. Based on the thermionic emission model, the forward current density at V > 3kT/q has the form [11] ... 

The FWHM of the XRD peak on GaN (1012)plane is an indicator of the total density of TDs. The XRD(1012) data of all samples are listed in Table 6.3. The (1012) FWHMs of GaN layers grown on porous TiN are smaller than those of their reference samples, indicating the effectiveness of porous TiN on defect reduction. 

An assessment of the amount of dislocation reduction can be made by directly counting the number of dislocations in plan-view TEM micrographs. The different efficacies of defect reduction in T63 and T68 are clearly revealed by Figure 6.21(a) and (b). The plan-view image in Figure 6.21(c) of the GaN reference sample shows a high density of edge/mixed dislocation arrays ( 1.5 x 109 cm-2) as marked by e , and... 

S. A. Chevtchenko, J. Xie, Y. Fu, X. Ni, H. Morko and C. W. Litton, Point defect reduction in GaN layers grown with the aid of SiN nanonet by metalorganic chemical vapor deposition , Proc. SPIE, 6473, 64730N (2007). 

E Yun, Y.-T. Moon, Y. Fu, K. Zhu, U. Ozgur, H. Morkof, C. K. Inoki, T. S. Kuan, A. Sagar, and R. M. Feenstra, Efficacy of single and double SiNx interlayers on defect reduction in GaN overlayers grown by organometallic vapor-phase epitaxy,/. Appl. Phys. 98, 123502 (2005). 

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