Abstract: A quartz reactor tube is provided with an electrically conductive hollow tube shaped into a coil surrounding but not contacting the outside surface of the quartz tube. The coil serves a double purpose of indirectly heating semi-conductor wafers within the quartz tube when the coil is energized with radio frequency energy, and serves to cool the outside surface of the quartz tube by directing air thereagainst through a large number of holes provided in the tubing. The air streams breakup a stagnant air insulating layer on the outside surface of the reactor tube in order to permit heat to be transferred from the tube to its surroundings. The cooler tube results in less gaseous material being deposited on its inside surfaces and thus increases the interval between reactor tube cleanings.