SanDisk and Matrix Semiconductor announced they have signed a definitive agreement for SanDisk to acquire Matrix. Matrix is a privately held company that has been developing and supplying 3-D integrated circuit, OTP (one-time programmable) technology since its inception in 1998. Matrix 3-D Memory is used for storage applications that do not require multiple rewrites and where low cost is the paramount consideration, such as video games, music, and other content, or for archiving. The Matrix technology can achieve low cost by building multiple layers of memory arrays on a standard silicon substrate so that active circuitry is not confined to the silicon surface but extends vertically as well. Because OTP technology is not rewritable once programmed, it complements rather than directly competes with Flash memory, which is rewritable but more costly.