Applied tunes up transistors for DRAM makers

摘要

Applied Materials recently introduced a series of chemistry and equipment changes. The move indicates the degree to which physics, chemistry, and the semiconductor-equipment industry must push ahead increasingly reluctant transistor performance in silicon-gate MOSFETs in the peripheral circuitry, including the address decoders, sense amps, and multiplexers, of advanced DRAMs. Unlike logic processes, which have converted to high-k/metal-gate MOSFETs at advanced nodes, DRAM processes have stayed with the significantly simpler silicon-gate stack. The array transistors in the memory cells have undergone an intense evolution, now employing recessed channels to get adequate performance at a tiny size. The peripheral tran-