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1.  Impact of oxidation and reduction annealing on the electrical properties of Ge/La2O3/ZrO2 gate stacks 
Solid-State Electronics  2012;74(5):7-12.
Highlights
► Ge surface passivation by scalable multilayer of La2O3/ZrO2. ► LaxGeyOz interfacial layers thickness controllable by oxidation time. ► Forming gas annealing improves Dit down to 3 × 1011 eV−1 cm−2 in presence of LaxGeyOz interlayer. ► Trade-off between interface trap density and equivalent oxide thickness.
The paper addresses the passivation of Germanium surfaces by using layered La2O3/ZrO2 high-k dielectrics deposited by Atomic Layer Deposition to be applied in Ge-based MOSFET devices. Improved electrical properties of these multilayered gate stacks exposed to oxidizing and reducing ambient during thermal post treatment in presence of thin Pt cap layers are demonstrated. The results suggest the formation of thin intermixed LaxGeyOz interfacial layers with thicknesses controllable by oxidation time. This formation is further investigated by XPS, EDX/EELS and TEM analysis. An additional reduction annealing treatment further improves the electrical properties of the gate dielectrics in contact with the Ge substrate. As a result low interface trap densities on (1 0 0) Ge down to 3 × 1011 eV−1 cm−2 are demonstrated. The formation of the high-k LaxGeyOz layer is in agreement with the oxide densification theory and may explain the improved interface trap densities. The scaling potential of the respective layered gate dielectrics used in Ge-based MOS-based device structures to EOT of 1.2 nm or below is discussed. A trade-off between improved interface trap density and a lowered equivalent oxide thickness is found.
doi:10.1016/j.sse.2012.04.004
PMCID: PMC3587347  PMID: 23483756
High-k; La2O3; ZrO2; Annealing; Oxidation; Germanate; Germanium
2.  Synthesis and electrical characterization of intrinsic and in situ doped Si nanowires using a novel precursor 
Summary
Perchlorinated polysilanes were synthesized by polymerization of tetrachlorosilane under cold plasma conditions with hydrogen as a reducing agent. Subsequent selective cleavage of the resulting polymer yielded oligochlorosilanes SinCl2 n +2 (n = 2, 3) from which the octachlorotrisilane (n = 3, Cl8Si3, OCTS) was used as a novel precursor for the synthesis of single-crystalline Si nanowires (NW) by the well-established vapor–liquid–solid (VLS) mechanism. By adding doping agents, specifically BBr3 and PCl3, we achieved highly p- and n-type doped Si-NWs by means of atmospheric-pressure chemical vapor deposition (APCVD). These as grown NWs were investigated by means of scanning electron microscopy (SEM) and transmission electron microscopy (TEM), as well as electrical measurements of the NWs integrated in four-terminal and back-gated MOSFET modules. The intrinsic NWs appeared to be highly crystalline, with a preferred growth direction of [111] and a specific resistivity of ρ = 6 kΩ·cm. The doped NWs appeared to be [112] oriented with a specific resistivity of ρ = 198 mΩ·cm for p-type Si-NWs and ρ = 2.7 mΩ·cm for n-doped Si-NWs, revealing excellent dopant activation.
doi:10.3762/bjnano.3.65
PMCID: PMC3458602  PMID: 23019552
chemical vapour deposition; field-effect transistor; oligosilanes; radiation-induced nanostructures; silicon nanowires; vapor–liquid–solid mechanism

Results 1-2 (2)