Characterization of carrier transport properties in strained crystalline Si wall-like structures in the quasi-quantum regime

摘要

We report the transport characteristics of both electrons and holes through narrow constricted crystalline Si "wall-like" long-channels that were surrounded by a thermally grown SiO_2 layer. The strained buffering depth inside the Si region (due to Si/SiO_2 interfacial lattice mismatch) is where scattering is seen to enhance some modes of the carrier-lattice interaction, while suppressing others, thereby changing the relative value of the effective masses of both electrons and holes, as compared to bulk Si. In the narrowest wall devices, a considerable increase in conductivity was observed as a result of higher carrier mobilities due to lateral constriction and strain. The strain effects, which include the reversal splitting of light- and heavy-hole bands as well as the decrease of conduction-band effective mass by reduced Si bandgap energy, are formulated in our microscopic model for explaining the experimentally observed enhancements in both conduction- and valence-band mobilities with reduced Si wall thickness. Also, the enhancements of the valence-band and conduction-band mobilities are found to be associated with different aspects of theoretical model.