Performance optimization
Control variables for performance optimization include heater
temperatures (powers), baseplate cooling, and reactor pressure.
A typical performance objective is to bring the wafers close to
a desired temperature,
while keeping wafer-to-wafer and across-wafer temperatures within
prescribed limits to avoid `cracking' of wafers and achieve
uniformity of wafers.
The above picture is the result of an optimization run with
the goal to compute heater powers to achieve a uniform temperature
distribution of 1027 C on the wafers during steady-state operation.
The picture on the left shows the resulting temperatures
in the middle of the wafers for the non-optimal, uniform
power distribution (solid line) and the
optimized power distribution (dashed line).
The picture on the right shows the resulting temperature
distributions inside the furnace. The percentages on
the right indicate the differences between the optimized power
distributions and the uniform power settings.
(Full picture)
