Simulating Longitudinal Temperature Bistability in a Silicon Wafer during Thermal Treatment in a Lamp Chamber

The possibility of the longitudinal bistability effect in a system of two parallel lightly-doped silicon wafers divided by a gas-filled gap with controlled width are studied experimentally and theoretically in a thermal chamber of rapid thermal processing set ups. Such a system models a silicon wafer of variable thermal conductivity coefficient between its top layer being in a high-temperature state and its bottom low-temperature layer in a mode of the longitudinal bistability effect in the wafer. It is shown that the longitudinal bistability effect can occur at a relatively small thermal conductivity coefficients of the gap which ranges from 10–2 to 10–1 W/(m K). Such a values of the thermal conductivity coefficient are three orders of magnitude less than thermal conductivity of silicon. As a result, the possibility of the longitudinal bistability in the silicon wafer during its heat treatment in the thermal chamber of rapid thermal processing set-ups is called into question.