Makyoh Topography Research Articles

The application of Makyoh topography for the study of GaAs layers grown by epitaxial lateral overgrowth

The surface morphology of GaAs layers grown by epitaxial lateral overgrowth is studied by Makyoh topography. Bending of the individual stripes of the layer are observed and quantified. Various defects related to the imperfections of the growth are also observed. The results are compared to surface-stylus and X-ray diffraction measurements. The results show that Makyoh technique is a useful tool for simple, fast and routine assessment of such structures.

Camera length and field of view in Makyoh-topography instruments

Makyoh topography is an optical method for the study of the large-scale morphology of mirror-like surfaces. Formulas are derived for the two basic parameters, the camera length and the field of view of Makyoh instruments. The relation between these parameters and the sensitivity are established. The formulas allow the proper design and setting of Makyoh instruments. Different types of Makyoh instruments are compared.

Geometrical optical model of the image formation in Makyoh(magic-mirror) topography

A geometrical optical model for the image formation of Makyoh (ormagic-mirror) topography is presented. General relations are given on theoptical settings. The basic equations of the imaging are derived. Fundamentalfeatures of the imaging are pointed out, and optimum working conditions areestablished. Simulations of the image of an isolated defect (hillock ordepression) and a periodic (sinusoidal) surface are presented for differentoptical settings. Supporting experimental images are presented.

Quantitative Makyoh topography

When a collimated beam of light is reflected by an approximately flat, mirror polished object and a screen is placed in the reflected beam some distance away from the object, a ‘‘magic mirror image’’ or Makyoh topogram of the object is formed on the screen. For objects with surface height variations, the topogram will not have a uniform intensity distribution, but even small height variations will show up strongly amplified as dark or bright patches/lines. Makyoh topography has been used for a number of years as a sensitive tool for the inspection of mirror polished surfaces, and in particular, semiconductor wafer surfaces. The main drawbacks of conventional Makyoh topography are, first, the ambiguity of interpretation because almost identical Makyoh topograms can result from an object with some given surface height profile and constant reflectivity, an object with constant surface height and a given nonuniform reflectivity profile, or an object with both height variations and a nonuniform reflectivity profile. The second drawback is the lack of quantitative interpretation, for example, surface height values cannot be obtained from the contrast in conventional topograms. I address these problems and describe a technique that for the first time enables the quantitative and unambiguous interpretation of Makyoh topograms.

Comparison of Experiments and Theories for Plastic Deformation in thermally processed GaAs Wafers

Different types of dislocation bundles were identified in thermally processed (001) GaAs wafers. Synchrotron based single crystal X-ray transmission topography, scanning infrared polariscopy, visible light interferometry, standard Nomarski microscopy, and Makyoh topography had been applied for this purpose and allowed for a classification of the dislocation bundles into one distinct majority and a generic minority type. The currently accepted theories are briefly discussed and it is shown that their disagreement with the core of the experimental observations is due to oversimplifications. A new theory is finally presented in a concise manner and its excellent agreement with all of the available experimental evidence is demonstrated.

A quantitative approach to Makyoh (magic-mirror) topography

A geometrical optical model of Makyoh-topography image formation is presented. Fundamental features of the imaging are established. Computer simulations and experimental images of a semiconductor wafer are presented to illustrate the model.

Makyoh Topography Study of the Curvature and Surface Morphology of Mismatched InGaAs/GaAs Heterostructures

The curvature and surface morphology of lattice-mismatched InGaAs/GaAs heteroepitaxial layers are studied by Makyoh (magic-mirror) topography. The results are compared to X-ray topography curvature measurements and theoretical considerations based on misfit relaxation models. The deviations suggest additional stresses, probably due to substrate effects, correlated with rough surface morphology.

Makyoh Topography Study of the Curvature and Surface Morphology of Mismatched InGaAs/GaAs Heterostructures

Makyoh Topography Study of the Curvature and Surface Morphology of Mismatched InGaAs/GaAs Heterostructures

Makyoh Topography for the Study of Large-Area Extended Defects in Semiconductors

A quantitative approach to the Makyoh-topography image formation mechanism is presented. General relations are given on the optical settings; geometrical optical simulations of a sinusoidal surface and a hillock (or depression) are presented. Optimum working conditions are established, and general features of the imaging are pointed out. The experimental images taken for Si wafers are compared to the results of the model.

Comparison of surface polishing techniques used for InP wafers

InP wafers prepared using different polishing and mounting methods were compared by Makyoh topography, which is capable of detecting extremely small surface height variations. In some wafers a cellular surface ridge structure due to uneven mounting wax distribution was observed. It is shown that the ridge structure can be completely eliminated by the optimisation of the wafer mounting procedure or by the use of a “free floating” double sided polishing technique.

Makyoh topography:comparison with X-ray topography

Makyoh (magic mirror) technology has been applied to the observation of slip lines and wafer warpage of Si wafers. Although Makyoh topography gives a bright field image and is not suitable for observing microflaws of micron-sized width and length, it has been shown that the method is capable of revealing slip lines as sensitively as X-ray topography. This is due to the ability of Makyoh topography to observe the slight waviness associated with microflaws in a defocused background image of macroflaws. This contradictory micro/macro observation capability was found to be due to different focal lengths of micro- and macroflaws (when the former is sharp, the latter is vague, and vice versa) and to the formation of composite images with neighbouring bright and dark areas which emphasise the image features vividly and impressively. Makyoh topography has also proven to be the most effective method to determine the optimum conditions for growing epitaxial wafers without slip lines and to check even a very slight drift from the optimum.