Shower head of a wafer treatment apparatus having a gap controller

A shower head for supplying a reactant gas to a process region within a reaction chamber during manufacture of a semiconductor device, the shower head comprising:

• a top plate having a gas port for introducing the reactant gas supplied from an outside source into the reaction chamber;
• a face plate disposed opposite the process region, the face plate having a plurality of through holes;
• a first baffle plate, having a plurality of through holes, the first baffle plate disposed between the top plate and the face plate so that it is capable of moving up or down, the first baffle plate having a top surface that defines a first gap for forming a first lateral flow passage of the reactant gas;
• a second baffle plate, having a plurality of through holes, the second baffle plate disposed between the first baffle plate and the face plate so that it is capable of moving up or down, the second baffle plate having a top surface that defines a second gap for forming a second lateral flow passage of the reactant gas between the first and second baffle plates;
• and
• a gap controller that is capable of variably adjusting a width of the first gap and variably adjusting a width of the second gap by varying a width of the gap controller so as to move at least one of the first and second baffle plates.