Details

Autor(en) / Beteiligte

• Yedave, Sharad
• Ying Tang
• Byl, Oleg
• Sweeney, Joseph

Titel

Silicon Tetrafluoride dopant gas for silicon ion implantation

Ist Teil von

• 2014 20th International Conference on Ion Implantation Technology (IIT), 2014, p.1-4

Ort / Verlag

IEEE

Erscheinungsjahr

2014

Quelle

IEEE Electronic Library (IEL)

Beschreibungen/Notizen

• Silicon Tetrafluoride (SiF 4 ) is a dopant gas of choice for different silicon ion implantation processes used in semiconductor device engineering. It is a primary source of atomic dopants like Si and F, and a potential source of molecular dopants (e.g. Si 2 , SiF x , x=1-3). A significant challenge associated with the use of SiF 4 is that it can compromise ion source performance, resulting in poor beam stability and source life. This is primarily the result of the formation of a halogen cycle that takes place due to the presence of fluorine from the SiF 4 molecule along with tungsten materials that are present in the ion source (e.g. liners, walls). A second challenge associated with SiF 4 can be limited beam current. In order to improve implant tool performance when using SiF 4 , the following investigations have been performed: (1) Characterization of SiF 4 / H 2 mixtures: The addition of hydrogen co-gas can effectively mitigate the halogen cycle and improve source performance. Using the magnitude of the resulting WF x peaks as an indicator, the degree to which the halogen cycle is mitigated is shown as a function of H 2 flow rate. Also, in that single packages may impart various advantages, SiF 4 / H 2 co-mixture stability data are provided. (2) Characterization of enriched (en) 28 SiF 4 : The additional enrichment can enable higher beam currents of 28 Si + . The effect of En- 28 SiF 4 flow rate on beam current is presented, along with the resulting WF x spectra. (3) Initial observations of SiF 3 + beams are provided, along with the potential benefits that may be obtained in selecting this molecular ion.