Chinese and American researchers from the University of Wisconsin-Madison and the U.S. Department of Agriculture have successfully created a semiconductor made almost entirely out of materials derived from wood. According to the scientists, the chips could be produced for only a fraction of the cost for the creation of regular semi-conductors. Furthermore, they are bio-degradable which also means a healthier ecosystem. Unfortunately, there's no way of knowing when and if such chips will be mass produced and how much would they cost since, according to the researchers, their price would vary depending on their application.
As far as I could comprehend, these bio-chips are made from cellulose nanofibril (CNF) which is a sturdy, flexible, transparent and has suitable electrical properties. Since cellulose is a substance found in every plant and the main component in the making of paper, you can imagine that finding and refining it shouldn't be a very costly process. In order to stop the chip from expending when heated, the CNF is coated with epoxy (a material made from thermosetting polymers).
According to the researchers, the CNF chips provide "high-performance electronics that are comparable to existing state-of-the-art electronics." Excited about the discovery, the team's leader, Zhenqiang “Jack” Ma, went on to say: “If commercializing the wooden chips, tremendous material cost will be saved. [..] We actually reduced the use of semiconductor material by 99.9 percent."