The enhancement of etch rate of silicon by heavy doping of phosphorus and arsenic atoms during cyclic selective epitaxial growth of silicon

In this study, the enhancement of the silicon etch rate with the heavy doping of phosphorus and arsenic was studied during cyclic selective epitaxial growth process using batch-type equipment. The reaction between molecular chlorine and heavily doped silicon was stimulated during the initial stage of cyclic SEG process at low temperature lower than 700 degrees C to induce voids at the interface. Heavy doping of n-type dopants into active regions also brought about the decrease in the growth rate of SEG process. It was possible to attain a stable process window by the elaborate control of total amount ratio of SiH4/Cl-2. The window provided the robust interface between SEG silicon and active regions as well as the selectivity to an oxide layer. Vertical diodes which were realized within the window revealed eligible on- and off-current characteristics for cell switches applicable to next generation cross-point memories.