Experimental and numerical investigation of the horizontal ribbon growth process

Abstract

Experimental and numerical results are presented on the process of horizontal ribbon growth (HRG) of single-crystal silicon. Experimental data on the leading edge position of the growth front as a function of pull speed is compared to model predictions with and without solidification kinetic effects. Without kinetics, the numerical results predict leading edge positions which are completely different than that observed in the experiment. With kinetics, the leading edge position is predicted typically within 1 mm and the change in position with pull speed also is well predicted. Conclusions from the kinetic model are that the growth occurs through a faceted process where the leading edge is a {111} facet that requires significant supercooling to maintain the growth. An outcome of the model is that the leading edge position versus pull speed response shows a turning point beyond which there are no steady growth solutions. This is consistent with all previously reported experiments on this process, which have reported maximum attainable pull-speeds. These results

Spatial–temporal stability analysis of faceted growth with application to horizontal ribbon growth

“…9, which also shows an initial element mesh used for the calculations. In [1], we showed that the model predictions of the location of the triple junction, x tj , as a function of pull speed agree well with that seen in the experiment. Fig.…”

“…Previous studies of horizontal ribbon growth did not consider these effects [3][4][5][6][7][8][9][10][11][12][13][14]. In [1], it was shown that facet kinetics limit the maximum growth rate attainable by FSM. This limitation manifested itself in the numerical results as a turning point in the response of the growth front position versus the pull speed; beyond a limiting pull speed no steady solutions could be found.…”

“…The full specification of the problem and the numerical method are given in[1]. To summarize, the governing equations are the same as used in the stability analysis: In the solid, the governing equation is the energy equation, which includes a convective term because of the translation of the solid with the horizontal pull speed, denoted u s .…”

Simulating the horizontal growth process of silicon ribbon

“…The liquid emissivity, ε l , equal to 0.2 and the solid emissivity, ε s , equal to 0.6. 15 In this case, the radiation heat flux function can be approximated as:…”

NeoGrowth silicon: A new high purity, low‐oxygen crystal growth technique for photovoltaic substrates

“…In the last 10 years, other new liquid crystallization options have arisen, undaunted by the market dominance of Czochralski (Cz) and multicrystalline (mc) ingot growth. Cast monocrystalline, Direct Wafer, low‐angle sheet silicon, and mushroom‐shaped crucible growth have each demonstrated promise in quality and/or silicon utilization, although none has broken through to large‐scale production. Meanwhile, the 2 big contenders, Czochralski pulling and multicrystalline casting, have seen tremendous amounts of continuous improvement and have grown to an enormous scale without a clear winner emerging .…”