drain regions this layer is deeper than the implant of act 107 however it is shallower than the implant act of 103 act 110 comprises heating the substrate to cause solid phase epitaxial re growth sper in the doped amorphous layers in both the extension and deep source drain regions mild heating such as in the temperature range from about 550 u00b0 c to about 700 u00b0 c for about 10 minutes to about an hour generally brings about crystal re growth for example a silicon crystal can generally be re grown by maintaining it at a temperature of about 600 u00b0 c for about half an hour crystals grow from the intact portion of the substrate beneath the amorphized layer preferably the dopants within the amorphous layer substantially maintain their as implanted concentration profiles during the sper process sper incorporates the dopants into the re grown crystal structure in substitutional sites the resulting active dopant concentrations can exceed about 2 0 u00d7 10 20 atoms cm 3 and preferably exceed about 2 5 u00d7 10 20 atoms cm 3 fig9 is a plot showing the typical dopant concentration profiles resulting from the acts 105 through 107 of the process 100 the y axis is the dopant concentration in atoms cm 3 and the x axis is depth in angstroms the tail implant provided by act 105 and indicated.