Prolonged Evaporation of Titanium
Original Publication Date: 1981-Jun-01
Included in the Prior Art Database: 2005-Feb-11
In certain applications such as the fabrication of integrated circuits, titanium is evaporated directly from a tungsten refractory metal boat using resistance heating to provide a titanium film. However, this method was found to have shortcomings in that the tungsten refractory boats had a relatively short life and the risk of losing silicon during film preparation was high. By adding 25g by weight of tungsten to the titanium source material, the boat life was effectively more than doubled. The additional tungsten added to the boat forms the correct molten phase, but the titanium, instead of reacting with the boat material, reacts with the added tungsten, thereby preserving the resistance boat life. By adding tungsten from previous refractory boats, a further saving is provided.