#3 Transmission, ALD
An infrared cell is used for transmission infrared characterization of adsorbates on silicon wafer and other transparent samples. The solid sample is placed in a gas cell limited by two sealing NaCl windows, which can be isolated from the main reactor volume during gas dosing by using gates valves. Silicon wafers are held on a nickel-made holder that can be heated resistively to 600°C and rotated to optimize the angle of incidence of the infrared beam. The complete gas cell can also be heated to ~200°C. A gas-handling system is used to pump this cell down to a few mTorr and to fill it with atmospheric pressures of the desired gases.
Techniques: Transmission IR, chemical vapor deposition/atomic layer deposition surface chemistry