Growth Controlled by Surface Integration

Surface integration is the process by which the growth units of the crystallizing material are incorporated into the crystal lattice after they have been transported to the crystal surface. Two main mechanisms controlling surface integration are described here. 

Equation (6.23) suggests that G is inversely proportional to 5 and is independent of L. However, hypothetically, when the diffusion layer thickness is large compared to the crystal size 28 L), Eq. 

In the mononuclear model, the limiting step is the formation of a nucleus. Once one is formed, the subsequent growth spreading across the crystal surface is infinitely rapid. For the polynuclear model, the spreading velocity is taken as zero and the crystal surface can only be covered by the accumulation of a sufficient number of nuclei. These two growth models represent two extreme cases. A third model, known as the birth-and-spread model, allows for formation of nuclei and their subsequent growth at a finite rate. In this case, new nuclei can form on top of uncompleted layers. 

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