Applied Materials, Inc.

Majeed Ali Foad

Babak Adibi

Mitchell C Taylor

In ion implantation processes for forming junctions in semiconductor devices, a proportion of ions implant into the semiconductor material beyond the desired junction depth due to channelling along axes and planes of symmetry in the crystal. A method is provided in which ions are implanted at a series of different energies starting with a lower energy than that required for the desired junction depth. The initial amorphising of the surface regions of the semiconductor during the lower energy implantation reduces the channelling probability when the ions are subsequently implanted at the full energy resulting in a more sharply defined junction.

Ion implantation method

In an efficient ion source BF.sub.3 gas is first passed over solid boron heated in an oven to at least 1100.degree. C. to reduce the BF.sub.3 to BF molecules. It is also proposed to use solid boron as feed stock by heating this in an oven to at least 1800.degree. C. to produce boron vapour. Either a reactive gas such as fluorine or an inert gas such as Argon is also introduced into the arc chamber to react with or sputter off boron condensing on the arc chamber walls.

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Horsham, United Kingdom

Majeed Ali Foad