Conditions for constant growth rate by LPE from a cooling, static solution

It is important to be able to grow crystalline layers at a constant rate in order to have good control over thickness, morphology, and composition. If LPE layers are grown from thin solutions over a relatively small temperature range an essentially constant growth rate can be achieved. The necessary conditions for constant growth rate are: (i) that t/gt{less-than or approximate}0.1, where t is the growth period, and τ the relaxation time associated with an Arrhenius liquidus curve and a steady cooling rate b; τ is given by τ = mC0 b, where m is the slope of the liquidus line at the initial temperature and C0 is the intial concentration of the solution, and (ii) that t/τ{greater-than or approximate}a2. The parameter a is in the range 3 x 10-2 to 10-1 where a is defined by the equation a= l ( DmC0 b) 1 2, in which l is the effective linear extent of the solution and D the diffusion coefficient of growth units in it. © 1978.