IMPROVEMENT OF HYDROGENATED AMORPHOUS-SILICON GERMANIUM ALLOYS USING LOW-POWER DISILANE-GERMANE DISCHARGES WITHOUT HYDROGEN DILUTION

We suggest that the role of hydrogen dilution in the improvement of th e quality of hydrogenated amorphous silicon germanium alloys is to alt er the relative contribution of the short and long lifetime precursors to film growth which are deleterious and beneficient, respectively. I n order to circumvent the preferential depletion of germane when mixed with silane, we have used low power disilane-germane discharges and t hereby obtained films with an optical gap < 1.5 eV having similar Urba ch tail width and defect absorption, with and without hydrogen dilutio n. (C) 1995 American Institute of Physics.