Correlations between process parameters, chemical structure and electronic properties of amorphous hydrogenated GexC1−x films prepared by plasma-enhanced chemical vapour deposition in a three-electrode reactor

Transition from amorphous semiconductor to amorphous insulator in hydrogenated carbon–germanium films investigated by IR spectroscopy

“…For the high ion energy a-S films are deposited while at ion energies lower then the transition threshold a-I materials are produced. Our early results of IR spectroscopy does not reveal any dramatic change in chemical structure (especially true for samples deposited at parameters close to transition conditions) which could be related to transition from a-I to a-S material [6]. The present results are obtained for films deposited at high and very low bombarding ion energy (far from transition threshold) what emphasizes differences.…”

“…This can be understood by the fact that molecular composition (ratio of Ge/(Ge + C)) also changes from 10% for a-I samples up to about 20% for a-S ones [6]. The molecular composition investigations were carried out only for films deposited from pure TMGe.…”

“…Preliminary results, obtained already in 1993, demonstrate that a-S samples are more cross-linked and can be characterized by higher concentration of germanium; however, no rapid changes in the chemical structure between a-S and a-I, contrary to their electronic structure, were observed [6].…”

“…This spectacular change of electronic structure can be caused by a small variation of plasma deposition parameters that are responsible for the impact energy of ions bombarding surface of the growing film [4]. On the other hand, values characteristic of deposited materials such as: material density, crosslinking, elementary composition display no rapid change related to the transition [5,6]. It is very interesting to find out how the electronic structure of a-Ge X C 1ÀX :H films is related to their chemical composition.…”

Characterization and Properties of Ge1–x–Cx:H Compounds Obtained by X‐ray CVD of Germane/Ethyne Systems: Effect of the Irradiation Dose

“…Note: GeH 4 , C 2 H 2 and all the gaseous products are considered. Tyczkowski et al [16] for films deposited starting from tetramethylgermanium. Analogous values are also obtained for solids produced using tetraethylgermanium in a magnetron reactor.…”