Diffusion coefficient of a pair of nitrogen atoms in float-zone silicon

Abstract

Outdiffusion profiles of nitrogen in silicon were measured by secondary ion mass spectrometry to determine its diffusion coefficient in a temperature range of 800–1200 °C. The total amount of the nitrogen outdiffusion agrees with the change in infrared absorption by heat treatment. The experimental results give the diffusion coefficient of nitrogen as D=2.7×103 exp(−2.8eV/kT)cm2/s. This value is five orders of magnitude larger compared with the reported expression of 0.87 exp(−3.29eV/kT)cm2/s. Nitrogen–nitrogen-pair-like molecule in crystals corresponds to the former value and substitutional nitrogen atom to the latter one. These two types of nitrogen in silicon may allow us to clarify the various effects of nitrogen such as strengthening of crystals and suppression of swirls and D-defect generation.

Ab InitioIdentification of the Nitrogen Diffusion Mechanism in Silicon

“…Both simultaneous and sequential movements of the nitrogen atoms were considered, with reported activation barriers of 3.3 and 2.9 eV, respectively. The second value for the energy barrier is fairly consistent with early data from Itoh and Abe [13], but outside of the confidence range given above. The 2.9 eV diffusion path moves the atoms from the ground state (usually named the antiparallel configuration) to the so-called Humble configuration (see Refs.…”

“…The darker points are FTIR data specific to nitrogen pair diffusion. A theoretical curve is also presented using the activation energy from Sawada et al [24], together with a diffusion prefactor from Itoh and Abe [13].…”

“…Except for the work of Gali et al [9], who calculated a binding energy of 1.73 eV, all theoretical investigations agree on a rather high binding energy between 3.67 and 4.3 eV [6,10 -12]. In contrast, the primary diffusion mechanism for nitrogen, in general, and the N 2 pair, in particular, has been disputed in the literature.In a variety of experimental investigations based on nitrogen outdiffusion from doped substrates [13] or on the indiffusion of nitrogen from the ambient [14 -17], the profiles obtained were interpreted in terms of the diffusion of N 2 as an entity. The diffusion data obtained are shown in Fig.…”

“…In a variety of experimental investigations based on nitrogen outdiffusion from doped substrates [13] or on the indiffusion of nitrogen from the ambient [14 -17], the profiles obtained were interpreted in terms of the diffusion of N 2 as an entity. The diffusion data obtained are shown in Fig.…”

Chemical approaches for doping nanodevice architectures

“…Until very recently only B-and P-containing molecules had been used in MLD studies. Limiting the anneal time to less than 5 s using advanced annealing techniques aids in the formation of sub-10 nm junctions in Si for dopants with fast diffusion rates, such as B and P. Despite the negligible electrical activity of N in Si [32,33], an alternative method was utilised by Guan and co-workers where N, a dopant with a low thermal diffusion coefficient, was introduced onto the Si surface using a standard hydrosilylation reaction. The use of boron molecular precursors that combine both the dopant molecule and a bulky backbone to act as a capping layer, in addition to containing a moiety with anchoring ability on the surface of non-deglazed Si wafers is beneficial to incorporate controlled doses of boron without potential deleterious carbon contamination.…”