Selective Tungsten Deposition Research Articles

Laser-Chemical Deposition and Etching on the Metallization Level of Integrated Circuits

AbstractLaser-controlled chemical deposition and etching techniques were used to modify integrated circuits. This work used a pulsed laser to initiate and control the etching, by chlorine gas, of aluminum conductors. New conducting paths were then formed by laser-chemical vapor deposition of highly-doped silicon from silane and diborane. Improved conductivity of laser-deposited connectors was achieved by the selective deposition of tungsten on the silicon. These techniques were used to “rewire” an integrated circuit allowing the full evaluation of the corrected circuit design.

Interfacial Tunnel Structures In Cmos Source/Drain Regions Following Selective Deposition of Tungsten

AbstractThe influence of B and As ion implantation on the location and density of interfacial tunnels, the extent of lateral encroachment, the amount of silicon consumed, and the crystallographic defects in CMOS source/drain structures following selective chemical vapor deposition of tungsten has been characterized.

Selective deposition of tungsten—prediction of selectivity

Preferential or selective chemical vapor deposition to a substrate region is based on a difference in thermochemical stability between different substrate regions. The higher this difference is, the higher selectivity is expected. In this paper a thermodynamic analysis of selective deposition of tungsten from H2 and WF6 on silicon regions in the presence of silicon dioxide is presented. At the initial stages of growth—silicon present in the vapor—the selectivity is favored by a low temperature, a low total pressure and a high WF6 concentration in the vapor. For the continuation—growth on the deposited tungsten—a low total pressure, a low WF6 concentration in the vapor and a higher temperature than that used initially should be chosen for highest selectivity. From the analysis it is also seen that simultaneous etching and tungsten oxide/tungsten deposition may occur on the silicon dioxide. The technique used to analyze the selective tungsten deposition process seems to be a useful tool for optimizing the selectivity in a given system and for reducing or eliminating undesired side reactions.

Kinetics and Mechanism of Selective Tungsten Deposition by LPCVD

Tungsten films have been deposited selectively on oxide‐patterned silicon wafers by the reduction of in and gas flow systems. The deposition rate of films was investigated as a function of reactant partial pressures. The reaction orders with respect to and are zero and one‐half, respectively. Under given experimental conditions, the growth rate of the selectively deposited W films was reduced by 32% when the deposition area increased by a factor of 10–100. This decrease in growth rate can be attributed to the effect of on the surface reaction. The selective nature of the process deteriorates with increasing deposition rate, partial pressure, partial pressure, or deposition time. The loss of selectivity seems to be linked to an increase in partial pressure in the reactor.

Formation of ultrathin tungsten filaments via selective low-pressure chemical vapor deposition

A new technique for the formation of ultrathin tungsten filaments is described. It is based on the selective deposition of tungsten via the silicon reduction of WF6 along the sidewall of a photolithographically defined undoped polycrystalline silicon/SiO2 step. The width of the filament is determined by the tungsten deposition parameters and the thickness by the thickness of the polycrystalline film. Filaments with a cross section of 600×2000 Å and 67.5, 140, and 265 μm lengths have been fabricated by this method. Initial low temperature resistance measurements of nonimplanted and Si-implanted (1×1015 cm−2, 20 keV) filaments show localization/electron-electron interaction behavior.