The invention provides an improved method for producing plate-shaped or tape-shaped silicon crystal bodies having pillar-like structures therein which are equivalent to columnar structures comprising conducting the sintering process, for purposes of particle enlargement, in a gas atmosphere comprised of argon and a minimum amount of hydrogen. In a preferred embodiment, the hydrogen concentration in such atmosphere is about 6% by volume. The so-produced silicon bodies are useful for further processing into large-surface solar cells.