The modification of Si nanocrystallites embedded in a dielectric matrix by high energy ion irradiation
We have followed the effects of heavy ion irradiation on the structural, electrical, and photoluminescence properties of ensembles of silicon nanocrystallites embedded in a dielectric (SiO2) matrix. This was done as a function of the irradiation dose and the content of the Si phase. The results obtained can be accounted for self-consistently assuming that a relatively small dose of the irradiation enhances the crystallization while for higher doses the irradiation enhances the amorphization. The corresponding processes suggest that tuning of the above properties can be achieved by swift heavy ion irradiation.
Ordered arrays of Si nanocrystals in SiO2: Structural, optical, and electronic properties
It is found that irradiation of SiO2 layers containing Si nanocrystals with high-energy heavy ions induces profound structural modifications—specifically, the formation of vertically ordered arrays of nanocrystals along the ion tracks. This effect results in substantial changes in the electrical properties (the conductivity and capacitance—voltage characteristics) and optical (photoluminescence) properties of the layers containing nanocrystals.
Phenomena in silicon nanostructure devices
Abstract.In nanostructures, whenever the electron mean-free-path exceeds the appropriate dimensions of the device structure, quantum natures may dictate the physical properties of devices. Among many important issues, some are selected in this work, whereas others, such as the reduction of dielectric constant, the increased binding energy of dopants, etc., are discussed briefly with references for further considerations. In the past several years, resonant tunneling via nanoscale silicon particles imbedded in an oxide matrix has shown striking similarity to the so-called soft breakdown (SBD), an important current subject in devices with ultrathin oxide gates. The relevance in applying results discussed here to SBD is discussed. A Si/O superlattice, a particular form of a new type of superlattice, semiconductor-atomic superlattice (SAS), is fully discussed. This Si/O superlattice can be used in silicon quantum and light-emitting devices. A diode structure with green electroluminescence has been life-tested for more than one year without degradation. High-resolution TEM shows defect density below 109/cm2. Preliminary calculation shows that the Si/O complexes result in a barrier height of 0.9 eV for silicon, sufficient for an epitaxially grown SOI, which is potentially far better than the SOI using buried oxide implantation followed by high temperature anneal.