THERMAL STRESS AND PLASTIC DEFORMATION OF THIN SILICON SLICES

Thermal stress and subsequent plastic deformation can be caused in a thin slice of silicon by temperature gradients which arise during the transient periods of heat cycling. They arise either because of the radiation shielding effect of neighboring slices in a parallel row of slices, or the heat sink effect of the boat on which the slices stand, or because of the effect of both. Spacing between the parallel slices, type of boat used, heating and cooling rates, and furnace temperature affect the temperature gradients and the amount of plastic deformation. Study of slip patterns showed that the tangential component of thermal stress was responsible for slip, and that multiple slip was more common than single slip under the conditions investigated. © 1969 The American Institute of Physics.