ABSTRACT
The development of the terrestrial solar cell manufacturing technology and the introduction of methods to improve its efficiency-like the chevron-shaped grid-resulted in producing them relatively inexpensive. But the basis of the terrestrial solar cells was still the silicon (Si) wafer, the price of which we had absolutely no control of. The purchase of Si wafers resembled the ride on a roller coaster.The primary source of the single crystal Si wafers came from the manufacturers who produced them for the semiconductor industry. The availability and cost of the wafers depended on how well the semiconductor industry was doing. If it was not doing well, there was no problem in obtaining wafers at the right price. When Si wafer manufacturers could not sell their production to the semiconductor industry, their salesmen would show up in my office and take me out for lunch. If, however, there was a great demand for wafers for the semiconductor industry, the same salesman would not even return my telephone calls. Wafer manufacturers happily sold only that small percentage of the total wafer production, the quality of which was not good enough for semiconductors at
a reduced price to the solar cell industry. For solar cells, even those wafers could be used. But as the solar business increased, more and more wafers were needed and if they were available, they were only at a very high price.The quality wafers used for the semiconductors were very high priced. The semiconductor manufacturers could afford to pay that price, because on a single wafer they made very many products, for example transistors or integrated circuits. On the other hand, one wafer was for us independent of its size, only one solar cell, depending on its size with one or more W output. The solar modules would not have been sellable if we would use Si wafers purchased at prices transistor or other semiconductor product manufacturers were able to pay for. It became evident from the beginning that to become successful and profitable in the photovoltaic business depended on the price at which we were going to be able to buy the Si wafers we needed for our growing production.We realized that at that time there was also a secondary market for the needed Si. Si ingots (rods) (before they were sliced up to become wafers) and wafers were manufactured for the semiconductor industry in a variety of quality, grades, and sizes some of which were for various reasons not used by the semiconductor manufacturers.To use these “left overs” we needed to develop a solar cell manufacturing technology, which was able to produce good solar cells on wafers of all kind of specifications and also to have the slicing equipment to buy ingots and to slice them. Solarex had an excellent technical staff and under the direction of Lindmayer and Wrigley they were able to develop a solar cell production technology, which was able to use practically any Si material.
