Hydrogen Transport in Phosphorus and Boron Dopedpolycrystalline Silicon

1999 ◽  
Vol 557 ◽  
Author(s):  
N. H. Nickel ◽  
I. Kaiser

AbstractHydrogen diffusion in phosphorus and boron doped polycrystalline silicon was investigated by deuterium diffusion experiments. The presence of dopants enhances hydrogen diffusion. The effective diffusion coefficient Deff is thermally activated and the activation energy varies between 0.1 and 0.4 eV. This is accompanied by a variation of the diffusion prefactor by 12 orders of magnitude. Using the theoretical diffusion prefactor the actual energy EA was calculated from Deff.EA also depends strongly on the Fermi energy and exhibits a similar dependence as the formation energies of H+ and H- in single crystal silicon.

1986 ◽  
Vol 71 ◽  
Author(s):  
T I Kamins

AbstractThe electrical properties of polycrystalline silicon differ from those of single-crystal silicon because of the effect of grain boundaries. At low and moderate dopant concentrations, dopant segregation to and carrier trapping at grain boundaries reduces the conductivity of polysilicon markedly compared to that of similarly doped single-crystal silicon. Because the properties of moderately doped polysilicon are limited by grain boundaries, modifying the carrier traps at the grain boundaries by introducing hydrogen to saturate dangling bonds improves the conductivity of polysilicon and allows fabrication of moderate-quality transistors with their active regions in the polycrystalline films. Removing the grain boundaries by melting and recrystallization allows fabrication of high-quality transistors. When polysilicon is used as an interconnecting layer in integrated circuits, its limited conductivity can degrade circuit performance. At high dopant concentrations, the active carrier concentration is limited by the solid solubility of the dopant species in crystalline silicon. The current through oxide grown on polysilicon can be markedly higher than that on oxide of similar thickness grown on singlecrystal silicon because the rough surface of a polysilicon film enhances the local electric field in oxide thermally grown on it. Consequently, the structure must be controlled to obtain reproducible conduction through the oxide. The differences in the behavior of polysilicon and single-crystal silicon and the limited electrical conductivity in polysilicon are having a greater impact on integrated circuits as the feature size decreases and the number of devices on a chip increases in the VLSI era.


1992 ◽  
Vol 276 ◽  
Author(s):  
Mitsuteru Kimura ◽  
Kazuhiro Komatsuzaki

ABSTRACTMicroheater made of heavily Boron doped single crystal Si beam covered with SiO2 film, 1000×300×3 μm, is fabricated on the n type Si substrate by the anisotropic etching technique. As this microheater has an air bridge structure of low resistivity semiconductor material with positive but small temperature coefficient of resistance, a broad heating area up to 800 °C is easily obtained and it has quick response with the thermal time constant t of about 4 ms and has small power consumption. Since this heating area is made of p type layer in the n type substrate,this area can be electrically isolated from the substrate because of the formation of p-n junction.


Author(s):  
Hayato Izumi ◽  
Ryota Mukaiyama ◽  
Nobuyuki Shishido ◽  
Shoji Kamiya

This paper reports the mechanical properties of single crystal silicon surface changed with hydrogen atoms trapped by underwater boiling treatment. Nanoindentaion test using a Berkovich indenter in six different indentation loads ranging from 100 μN to 1000 μN was conducted to obtain the load-displacement curve. The energy dissipated in plastic deformation, i.e. plasticity energy, during indentation on silicon wafers with different carrier concentration (undoped, lightly and heavily boron doped silicon) were compared. After boiling treatment, increment in the plasticity energy was observed on silicon containing boron. This result suggests that hydrogen atoms trapped inside silicon enhanced dislocation mobility leading to larger plastic deformation.


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