

Pulsed laser deposition (PLD) is widely used in the materials processing industry. With this technique, multi-component materials can be ablated from the the target and deposited onto a substrate to form stoichiometric layers which match the target material. A basic PLD system has been set up at Colorado State University. Figures show a schematic diagram of the CSU system. A krypton fluoride (KrF) excimer laser with a wavelength of 248 nm (Lambda Physik model LPX 305 i) is used as the energy source. The maximum output energy of the laser is about 1200 mJ per pulse at a pulse duration of 25 ns. The maximum repetition rate is 50 Hz. The laser beam is focused into a rotating target stage and it is rastered using a stepper motor driven mirror. The target angle of incidence is 45 degrees. The laser spot size on the target surface is about 0.1 mm2. A mechanical rotary pump (HyVac 55L) and a turbomolecular pump (Electrorava ) are used to evacuate the vacuum chamber. The chamber can be pumped down to a base pressure of 2.5 X 10-7 Torr. A baratron (MKS 127A) and ionization gauge are used to detect the pressure of the chamber in a range 10-3 - 10-7 Torr. The oxygen pressure in chamber is controlled with an MKS 651C pressure controller and an MKS 247C four-channel readout. The substrate heater (Blue Wave Semiconductor) can be operated from high vacuum (10-7 Torr) up to an oxygen pressure of 1 atmosphere. The maximum temperature of operation in vacuum or in an oxygen atmosphere is 900 oC. The substrate heater can be used at temperatures up to 950 oC for short periods (up to 30 min).