A Novel Tungsten Gate Technology for VLSI Applications

Due to their low resistivities, refractory metals such as W and Mo have been investigated as the gate electrodes and interconnections for VLSI [1]. However, these metals cannot withstand high temperature oxidizing ambients, which has imposed a constraint on MOSFET fabrication. For this reason, poly Si and refractory metal silicides have been widely used for the gate material[2,3], although their technology faces limitations for VLSI of very high integration, such as 1 Mb or higher, where low resistivity is desired.