Article 2

The real competition for CZ silicon comes from multicrystalline silicon, which has been increasing its market share at the expense of CZ. While in 1999 each had a 42 % share of total cell production, the balance probably shifted in favor of multicrystalline in 2000, since the world's leading cell manufacturers, Kyocera and Sharp, both of which us this technology, ramped up their capacities to 60MW and 54 MW respectively. The reasons for the strength of multicrystalline technology are simple: The throughput with the CZ process is only about 1.5 kg/hour, and for the multicrystalline process about 3.5 kg/hour, with energy and material costs being much lower. The problem with standard CZ processing is that it is a batch process, requiring the furnace to be brought up to temperature in order to melt the raw silicon in the crucible before a single crystalline ingot is pulled. Then the furnace is cooled down prior to loading a new charge at which time the crucible breaks, requiring replacement.
In cooperation with the Oregon based company, Jax Industries, Siemens Solar has developed a CZ silicon recharge process, where new silicon raw material is recharged from a hopper, which is in a vacuum and controlled via 2 valves. By using a continuous batch recharge, the oven can be kept at temperature and the same crucible can be used for many runs.
Siemens engineers have done as many as 12 consecutive recharges using the same crucible with Jax Industries recharge system. Recent tests at the Siemens facility in Vancouver have shown that by using the Jax recharge system, the power consumption could be reduced by 51 percent per run, the use of argon reduced by 85 percent per run, and the productivity increased by 35 percent, resulting in a 30 percent reduction of ingot costs and 15 percent higher yields. By the end of the year, all of the crystal growers at Siemens Solar are expected to be equipped with the Jax Industries recharge system.
While the process for growing multicrystalline silicon will still have a higher throughput level and use less energy, such improvements to the CZ growing process will help CZ silicon growers to catch up. All of which means monocrystalline and polycrystalline silicon technology will easily have a secure future over the next ten years - despite what the disciples of thin-film technologies would like to believe.