Properties of Hydrogenated Amorphous Silicon-Germanium Alloys Deposited by Dual Target Reactive Magnetron Sputtering

Authors

Samuel J. Levang, Macalester CollegeFollow

Document Type

Honors Project On-Campus Access Only

Abstract

Hydrogenated amorphous silicon-germanium alloy thin films (a-Si_1-xGe_x:H) were deposited using reactive magnetron sputtering. Dual targets of silicon and germanium were sputtered in an argon + hydrogen atmosphere using RF excitation. Films with x = 0.4 were deposited as a function of substrate temperature and hydrogen partial pressure, and were evaluated by dark and photoconductivity, infrared absorption, and optical transmission. Photosensitivity reached a maximum value of about 4500 between 150 and 200°C. Using the stretching modes in the region of 2000 cm^-1, the hydrogen bonding was characterized in terms of the preferential attachment ratio (PA), which represents the ratio between H bonded to Si and H bonded to Ge. The PA shows a systematic increase with increasing temperature, generally independent of hydrogen partial pressure. The interplay between thermodynamic and kinetics effects in determining PA and film quality is discussed.

Recommended Citation

Levang, Samuel J., "Properties of Hydrogenated Amorphous Silicon-Germanium Alloys Deposited by Dual Target Reactive Magnetron Sputtering" (2012). Physics and Astronomy Honors Projects. 13.
https://digitalcommons.macalester.edu/physics_honors/13