Laser processing of tungsten from WF6 and SiH4

Low temperature laser processing of W using WF6 and SiH4 is discussed. This process can be applied with limited thermal budget to various substrates, giving the possibility of depositing thin films on fragile substrates like polyimide or GaAs. In a direct writing mode, an Ar+ laser and a diode laser have been used to produce WSix with various controlled line profiles on polyimide and TiN. Best resistivities are between 40 and 80 μω·cm and the composition W/Si vary from 1.4 to 1.8. Excimer laser induced deposition of W on GaAs for making Schottky contacts has also been investigated. This process yields pure α-W deposits with resistivities of 20 μω · cm.