Measurements of conductance fluctuations in coplanar hydrogenated amorphous silicon (a-Si:H) are reported as a function of surface etching treatments. The noise power spectrum displays a broadened Lorentzian peak, associated with surface damage by CF4 reactive ion etching (RIE), whereas surface etches using ion milling or wet chemicals remove the Lorentzian spectral feature and only a 1/f spectral form for frequency f is observed. The Lorentzian spectral feature can be explained by trapping-detrapping from surface states induced by the RIE etch, which cause fluctuations in the depletion width of the space charge region near the film surface. The thermally activated Lorentzian corner frequency is a measure of the degree of band bending and the Fermi energy at the thin film surface.
|Original language||English (US)|
|Number of pages||6|
|Journal||Materials Research Society Symposium - Proceedings|
|State||Published - Jan 1 1999|
|Event||The 1999 MRS Spring Meeting - Symposium A 'Amorphous and Heterogenous Silicon Thin Films: Fundamentals to Devices' - San Francisco, CA, USA|
Duration: Apr 5 1999 → Apr 9 1999