SINGLE AXIS COMBINED ION AND VAPOUR SOURCE

摘要

An ion chamber 1 houses a crucible anode 2 containing ion source material 3 and connected to a positive power supply. A cathode 5 is heated by current from source 7 and an electric field is established between the cathode and anode by voltage source 6. A DC bias is established by second voltage source 11. A second anode 15 is connected to the anode 2 by variable resistor 16. The chamber 1 is covered by a DC biassed grid 12 and is filled with ionizable gas via inlet 40.
By varying the resistor 16 from a low value to a high value the cathode/anode current can be shifted from the auxiliary anode 15 to the crucible anode 2 thereby varying the rate of evaporation of the source material. This gives rise to an evaporant stream 8. At the same time the gas is ionized to form an ion beam 14.