Vaporiser for generating feed gas for an arc chamber

Semi conductor implant apparatus having an ion source comprising an arc chamber and a vaporiser connected to supply a feed gas to the arc chamber, the vaporiser comprising an elongate crucible arranged to contain a source of material, a heater to heat the source to generate the feed gas, and a cooling duct arranged to extend along substantially the entire length of the crucible to receive cooling fluid and cool the source of material.

A method of controlling the generation of a feed gas for the arc chamber of an ion source, comprising the steps of

• a) providing in a crucible a quantity of non gaseous material which can be heated to generate a desired feed gas for the arc chamber,
• b) heating the crucible to a temperature at which said desired feed gas is generated and supplying the generated feed gas to the arc chamber, and
• c) stopping the supply of said desired feed gas by halting said heating and applying forced cooling to said crucible.

A method of controlling the temperature of a crucible for generating, from non-gaseous material contained in the crucible, a feed gas for the arc chamber of an ion source, the method comprising the steps of

• a) applying a heating current to a heating element to heat the crucible so as to generate said feed gas, and
• b) simultaneously applying an amount of forced cooling to the crucible so that the crucible is heated by said heating current to a desired temperature.