Title :
A selective LPCVD tungsten process using silane reduction for VLSI applications
Author :
Tsutsumi, Toshiaki ; Kotani, Hideo ; Komori, Junko ; Nagao, Shigeo
Author_Institution :
Mitsubishi Electr. Corp., Hyogo, Japan
fDate :
3/1/1990 12:00:00 AM
Abstract :
A selective CVD tungsten process using silane reduction of tungsten hexafluoride has been investigated. A deposition rate as high as 0.6 μm/min is obtained. The properties of the tungsten films have been investigated by X-ray diffraction, secondary ion mass spectroscopy, and transmission electron microscopy. The tungsten films contain a small amount of Si, which is uniformly distributed as a W5Si3 phase. The silane reduction process completely suppresses undesirable phenomena, such as Si consumption, lateral encroachment, and wormholes. Measurements have been made of the junction leakage current and the contact resistance. The junction leakage current for this process is almost the same as that for the conventional AlSi process. The contact resistance of submicron holes is more stable and lower for this process than for the conventional one. The new process has been successfully applied to CMOS 1-Mb DRAMs
Keywords :
CMOS integrated circuits; VLSI; X-ray diffraction examination of materials; chemical vapour deposition; contact resistance; integrated circuit technology; integrated memory circuits; leakage currents; metallisation; random-access storage; secondary ion mass spectra; transmission electron microscope examination of materials; tungsten; 1 Mbit; CMOS DRAM; SiH4; VLSI; W film; W5Si3 phase; WF6; X-ray diffraction; contact resistance; deposition rate; interconnection; junction leakage current; secondary ion mass spectroscopy; selective LPCVD W process; silane reduction; submicron holes; transmission electron microscopy; wormholes; Contact resistance; Current measurement; Electrical resistance measurement; Leakage current; Mass spectroscopy; Semiconductor films; Transmission electron microscopy; Tungsten; Very large scale integration; X-ray diffraction;
Journal_Title :
Electron Devices, IEEE Transactions on
