Nano-sized silicon particle formation in high density silane plasma and its applications

Study of nano-sized particle formation in processing plasma has received increased attention in recent years. On the one hand, particle generation is considered harmful in the semiconductor industry and on the other hand particles generated with specific size, composition and crystallinity are useful for many electronic, optoelectronic and magnetic applications. It has become especially necessary to find methods to control the size, concentration, crystallinity, and composition of particles given the fact the particles with a give size and composition have become useful. This research thesis investigates several fundamental issues of nano-sized particle formation in high density plasma. The emphasis is on conditions that generate non-agglomerated, extremely monodisperse silicon particles. Characterization techniques and analyzing methods are developed to understand nano-sized silicon particle electrical properties. We also exploited other new applications based on nano-sized silicon particles which have not been developed, such as nano-particle Schottky Barrier transistor. Based on this idea, a silicon only technology would permit three-dimensional circuits.; The following are the key results: (1) Three regimes are mapped out from our experiments: a no particle domain, a poly-disperse and agglomerated domain, and a mono-disperse domain. In a mono-disperse domain, particle diameter is highly uniform with the relative standard deviation ranging from 0.03 to 0.13. The addition of hydrogen to the plasma tends to increase the crystallinity of the nanoparticles. (2) The novel device structure was demonstrated by TCAD simulation and device morphology measurement. The charge transport characteristics in nano-sized amorphous silicon particles was studied at different temperature over a wide range of applied voltage. The analysis of current-voltage-temperature characteristics of the new device provides a good fit to the theory and explains some of the measured results in the term of traps in the energy gap. (3) Promising characteristics of novel particle SBMOSFET have been described on the basis of ISE-TCAD. Details of energy-band, electron density and current density profile in particles are presented. The lowest electron density is directly under the gate region, and undesirable effects of the interface at the gate on the electron transport are substantially reduced.