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By applying liquid phase epitaxy, we have grown defect-free silicon and silicon–germanium layers on partially oxide-masked Si wafers. The growth of the layers started epitaxially in oxide-free seeding areas and proceeded laterally over the thermal oxide film. Detailed studies by x-ray topography and electron microscopy show that the obtained thin semiconductor-on-insulator layers bend towards the oxide during lateral growth. The bending of the layers can be ascribed to adhesion and interfacial forces. Adhesion operates across a gap between the closely spaced surfaces of the oxide and the epitaxial Si and facilitates lateral growth of high-quality semiconductor layers on dissimilar layers or substrates. The technical potential of adhesion-dependent solution growth on dissimilar substrates is discussed.

a b s t r a c tSeveral industrial n-type Czochralski silicon ingots were analysed on wafer and cell levels with ECN's bifacial n-type solar cell process. In some of the ingots, the solar cell performance in the very top drop of about 1% absolute with respect to cell from the middle part of the ingot. These cells show typical ring shaped pattern. After receiving a post-process anneal treatment at 200 1C, the efficiency nearly completly recover. We demonstrated that the improvement is due to bulk lifetime enhancement. The recovery is stable in storage conditions, under illumination and high temperature treatments up to 600 1C. The same effect cannot be reproduced in p-type Cz silicon solar cells with similar ring shaped patterns. This indicates that the defects responsible for lifetime and efficiency degradation in wafers affected by ring patterns differ in n-type and p-type.

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