  We have designed and constructed a compact rotary substrate heater for the
temperature range from 25 $^\circ$C to 700 $^\circ$C. The heater can be
implemented in any deposition system where crystalline samples are needed. Its
main function is to provide a heat treatment in situ during film growth. The
temperature is monitored and controlled by a temperature controller coupled to
a type K thermocouple. A heater case was designed to host a resistive element
and at the same time to allow the substrate holder to freely rotate. Rotation
is crucial not only for film homogeneity during deposition but also for the
elimination of temperature gradients on the substrate holder. To tolerate
oxidizing and corrosive environments, the instrument was made of stainless
steel which also works as "coolant" taking advantage of heat dissipation. The
instrument performs well for long periods of time with stable temperatures. We
hope that this project is useful for laboratories wishing to have a compact
rotary heater that meets the requirements for crystal growth and film
homogeneity.
