Layer growth macrosteps

Layer Growth. In Section 7.9 we showed that many monoatomic steps can unite (bunch, coalesce) to form polyatomic steps in the presence of impurities. Additives can also influence the propagation of microsteps and cause bunching and formation of macrosteps. 

Two processes are involved in the layer growth of crystals, viz. the generation of steps at some source on the crystal face followed by the movement of layers across the face. Consideration of the movement of macrosteps of unequal distance apart (BCF theory considers a regular distribution of monoatomic steps) led Frank (1958) to develop a kinematic theory of crystal growth. The... 

Steps, or growth layers, are structure components for construction of a variety of growth forms in the electrodeposition of metals (e.g., columnar crystals, whiskers, fiber textures). We can distinguish between monoatomic steps, polyatomic microsteps, and polyatomic macrosteps. Only the propagation of polyatomic steps can be observed directly, in situ. 

Fig.7.154. Layer type of growth for copper deposition showing macrosteps with irregular edges.

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