On metastable properties of plasma treated amorphous Si:H thin films

Amorphous hydrogenated silicon (a-Si:H) is well known as a semiconductor with metastable properties. This paper deals with structural and electrical properties of a-Si:H surfaces in virgin state as well as on low-energy ion exposition. Two ion sources were used, namely a monoenergetic ion beam produced by Kaufmann source and ions extracted by the plasma immersion ion implantation technique (PIII). The structural and electronic changes induced by ion impacts, as investigated by the X-ray diffraction at grazing incidence, capacitance-voltage measurements and charge version of deep level transient spectroscopy (Q-DLTS) are reported. The changes induced in the gap-state distribution of a-Si:H due to an interaction with low energy Ar+ ions followed in situ by the short exposure to both hydrogen/oxygen ion beam or to molecular high-purity oxygen are presented. The X-ray measurements confirmed that the most important reflection, which enables us to trace the evolution of the structural changes of a-Si:H layers caused by ion impacts, has the position at 2q ~ 28°. It is related to the existence of Si80H20 complexes inside the layer. The existence of only two types of deep metastable distributions Dz and De was observed in MIS structures prepared for the first time by the plasma immersion ion implantation technique. The distribution corresponding to positively charged defects Dh is missing. The use of the standard monoenergetic ion beam technique for the preparation of MIS structure confirmed the existence of three types of deep metastable distributions in a-Si:H (Dh, Dz and De). The differences in the results are explained by the application of a relatively high negative potential (1000 V) on the sample during the PIII experiment

Low-energy argon ion beam treatment of a-Si:H/Si structure

The results of several surface-sensitive techniques applied to the investigation of ion beam-treated a-Si:H/crystalline silicon structures, such as deep-level transient spectroscopy (DLTS), photoluminescence at 6 K and room temperature, and X-ray diffraction at grazing incidence (XRDGI) are presented. Three important results follow from this contribution. (i) Two groups of gap states with thermal activation energies of 0.71 and 0.84 eV were identified and found to be sensitive to illumination, this property exhibiting metastable character; we suppose effects similar to those observed in the porous silicon/silicon and a-Si:H/silicon structures. (ii) Broader luminescence peaks were identified optically with the energies lying in the range of 0.7 to 0.95 eV, the most distinct one being at 0.85 eV. (iii) X-ray reflection at 2θ∼28° has been found as the reflection suitable for tracing the structural properties of a-Si:H layer

On a transformation of a-Si:H surface due to very low-energy particle impacts to very thin insulating overlayer of device quality

A chapter on a transformation of a-Si:H surface due to very low-energy particle impacts to very thin insulating overlayer of device qualit

Research and development of the thin film layer systems used at the production of amorphous and heterojunction solar cells

This chapter looks at the research and development of the thin film layer systems used at the production of amorphous and heterojunction solar cell

On interaction of low-energy particles with a-Si:H and a-SiGe:H thin films

A chapter on the interaction of low-energy particles with a-Si:H and a-SiGe:H thin film

Optical, structural and electrical properties of a-Si:H

This paper looks at optical, structural and electrical properties of a-Si:

Transformation of semiconductor surfaces due to low-energy particle impacts

This paper looks at the transformation of semiconductor surfaces due to low-energy particle impact

On structural properties of a-Si based semiconductors

A chapter on structural properties of a-Si based semiconductor

On interaction of RF plasmas and amorphous silicon

A chapter on interaction of RF plasmas and amorphous silico

Properties of semiconductor surfaces covered with very thin insulating overlayers prepared by impacts of low-energy particles

This paper deals with the formation of very thin insulating layers on crystalline (GaAs) and amorphous semiconductors (a-Si:H and a-SiGe:H) prepared by the impacts of particles of a very low energy. Plasma, ion beams and plasma immersion ion implantation (PIII) as the sources of impacting particles were used and compared. The last technique was applied successfully for the first time in the case of amorphous silicon-based semiconductors. More diagnostics techniques were used for the investigation of the transformation of the semiconductor surface properties. In the a-Si:H based MOS structures prepared by PIII technology, only two groups of defects 0.82 and 1.25 eV (D(z) and D(e), respectively) were found. We suppose that the PIII technology using the implantation at the sample voltage of ca. -1000V causes the formation of a-Si:H layers with missing group of D(h) states. The only decisive parameter determining the formation of two groups of states is the negative potential of the sample during the implantation. In aSiGe:H based MOS structures, three distributions could be prepared by a bias annealing procedure: 0.47, 0.58 and 0.95 eV corresponding to p-type (D(h)) intrinsic (D(z)) and n-type (D(e)) distributions, respectively