Fabrication of polysilicon plugs for deep-submicron contact-holes

Summary form only given. Contact holes with diameters down to 150 nm have been successfully plugged with polysilicon using a double-deposition low-pressure chemical vapor deposition (LPCVD) and double-phosphorus diffusion process. A 510 degrees C poly-Si deposition temperature was found to yield films with better contact-hole step coverage and lower resistivity than higher-temperature films. The contact resistance of 200-nm-diameter contact holes was measured to be below 100 Omega . This polysilicon plug process has been used for 64-MDRAM bit-line contacts.<>