DURHAM, N.C., April 17 -- Cree Inc. has signed a definitive agreement to acquire privately held Nitres Inc., a developer of nitride-based semiconductor devices. The terms of the agreement call for Cree to acquire all outstanding and vested shares of Nitres stock in exchange for approximately 1.5 million shares of Cree common stock in a pooling-of-interests transaction. In a related transaction, Cree will issue approximately 350,000 unvested Cree shares in exchange for unvested Nitres shares; Cree also will assume all outstanding Nitres stock options and warrants, which will be exercisable for approximately 150,000 shares of Cree common stock. Following the acquisition, which the companies expect to be complete by the end of May 2000, Nitres will become a wholly owned Cree subsidiary known as Cree Lighting Co.Based in Westlake Village, Calif., Nitres has designed and demonstrated nitride-based LEDs in the ultraviolet-to-blue range (400- to 410-nm peak wavelength) with a quantum efficiency of 20 percent, which Nitres said is believed to be the highest ever reported. As commercialization efforts progress, Cree expects the Nitres technology to complement Cree's SiC device manufacturing process, and to enable development of new solid-state light engines for commercial applications.