Semiconductor memory device

Abstract

In this semiconductor device, contact holes extending from a lower interconnection layer containing diffusion layers at the surface of a Si substrate to an Al-involved interconnection layer formed above the Sis substrate through the intermediation of an interlayer dielectric film are filled with Al alloy having a eutectic point lower than that of Al-Si alloy. Then, for example, an Al-Ge alloy is sputtered, reflowed and allowed to react with the Si film to convert into an Al-Ge-Si alloy. At the stage of forming the Al-Ge-Si alloy, the reflow ceases. This brings the reduction of junction leakage current from the diffusion layers. Similarly in the case of a high aspect ratio of contact hole, this technique enables the contact hole to be fully filled with the above-mentioned Al alloy. Besides this technique enables direct interconnections in multilayer Al-involved interconnection structure of between an upper-layer Al-involved interconnection and diffusion layers, contributing to reduction of area required for interconnections.