A customer was recently asking about “spitting” when using E-Beam Evaporation for Oxide materials. While different types of materials are more likely to “spit” than others, generally “Spitting” can usually be resolved by proper rise and soak times. However, if the material being used is a simple low density hot pressed material it may have porosity and voids in the material, which are actually trapped gas pockets, they are likely expanding upon heating and “Blowing Up” the charge. A Hot Isostatically Pressed (HIP’ed) material of high density would be less likely to spit. Extended rise soak times should help the material to outgas in the system. As far as the resultant films are concerned, thermal evaporation is prone to fractionation (disassociation) and some amount of free elemental oxygen may be released into the chamber and be pumped away.
