Investigation of the surface preparation of GaAs substrates for MBE and VPE with whole sample optical reflection

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

“…cos ϕ and cos 2ϕ take into account the flux change due to nonnormal incidence at the sample and the screen, respectively (as the screen is perpendicular to the z-axis, the angle of incidence at the screen is 2ϕ). Equation (4) has been evaluated in terms of the intrinsic geometry of the reflecting surface in reference [9]. The result, using our notation, is (see equations (19) and (22) of [9])…”

“…The cells of the grid represent the pencil's cross section upon reflection from the surface. The screen illuminance at a screen point is therefore inversely proportional to the area of the cell image in the screen (see equation (4)). Note also that an additional piece of information is contained in the grid image, since in the illuminance value the shape of the pencil's cross section is lost.…”

“…The reported sensitivity of the method is a 0.4 µm height difference over a 10 mm distance and 50 nm over a 0.5 mm distance [3]. Makyoh topography has proven its power, for example in detecting flaws induced by wafer slicing, polishing and lapping [4,5] and defects in directly bonded Si wafers [6]. Makyoh-topography instruments are also available commercially.…”