This study analyses the heterogeneity in the speed of capital structure adjustment. Using a doubly-censored Tobit estimator that accounts for mechanical mean reversion in leverage ratios, the speed of adjustment is 25% per year in a large international sample, supporting the economic relevance of the trade-off theory. Differences in the adjustment speed across financial systems are attributable to differences in the costs of adjustment. Macroeconomic and micro-level supply-side constraints also affect the dynamics of leverage. Firms adjust more slowly during recessions, and the business cycle effect on adjustment speed is most pronounced for financially constrained firms in market-based countries.

GaN layers are laterally overgrown by metalorganic chemical vapor deposition on structured Si(111) substrates in a single growth process. The substrates are structured with parallel grooves along the Si 〈1–10〉 or perpendicular to the Si 〈1–10〉 direction by standard photolithography and subsequent dry etching. Due to the anisotropic chemical dry etch process, the remaining Si ridges are underetched. The GaN layer grows nearly exclusively on the bottom of the grooves and on the top of the ridges between the grooves. These two growth fronts are completely separated from each other. As a consequence, the GaN layer growing from the ridge area between grooves can extend over the grooves. This process is similar to the so called pendeo-epitaxy process, but is completely mask free during growth and does not require any growth interruption. The improvement of the crystalline and the optical quality of the GaN layer is demonstrated by atomic force microscopy and cathodoluminescence spectroscopy.

The formation, prevention and removal of micropyramids at the {100} bottom of anisotropically etched cavities are investigated and discussed. In the case of pure KOH solutions the base of micropyramids has been found to be always rectangular or octagonal shaped. The formation is independent of the KOH supplier and the etchmask opening process. The arrangement of the rectangular based micropyramids on the {100} etch bottom depends on the etching time, etching position of the chip (vertical or horizontal) and on the oxygen content in connection with the thermal history of the wafer material. For both types of micropyramid the surface density and size increase with decreasing KOH concentration and etching temperature. Moreover the proportion of octagonal micropyramids rises in those conditions. The origin is discussed in terms of micromasking by H 2 -bubbles in connection with plateau generation and layer by layer peeling of {111} planes. Other mechanisms which are suggested in the literature are discussed. Furthermore it was exhibited that already arisen micropyramids can be removed by a short re-etching in the same etch bath in the same conditions.

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