Tungsten metallization onto InP prepared by rapid thermal low-pressure chemical vapor deposition of WF6 and H2

Abstract

Tungsten (W) films were deposited onto InP in a cold wall, rapid thermal low-pressure chemical vapor deposition (RT-LPCVD) reactor, using a tungsten hexafluoride (WF6) gas reduced by hydrogen (H2). W films of thickness 50–450 nm were deposited in the temperature range of 350–550 °C, pressure range of 0.5–4.5 Torr, and deposition rates up to 4 nm/s with an apparent activation energy of about 1.12 eV. The film stress varied depending on the deposition pressure, from low compressive (deposition at 0.5 Torr) to moderate tensile (deposition at about 4.5 Torr). Post-deposition sintering of the W films at temperatures up to 600 °C led to reduction of the resistivity with a minimum value of about 55 μΩ cm as a result of heating at 500 °C.