Further expanding their alliance in semiconductors, AT&T Co and NEC Corp announced yesterday that they have established a Tokyo-based joint marketing venture that AT&T hopes will boost its Japanese sales 2.5 times by 1994: NEC is going to reach a set of customers through its distribution channels that we on our own would never be able to reach, William Warwick, president of AT&T Microelectronics said; the new company, AT&T Japan Semiconductor Marketing Ltd, is looking for turnover of some $80m by 1994, some of which will come from NEC chips that complement AT&T’s product range; NEC said it was pleased that the venture would help increase the US share of Japan’s semiconductor market, which has been such a source of trade friction in recent years; the new company will sell AT&T’s field programmable gate arrays and other application specific integrated circuits, high-speed static RAMs and some NEC parts; AT&T owns 51% of the new company.