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Thermal diffusion process is being used on a p-type base Si wafer of 1017 cm-3 background acceptor concentration (NB) in

Posted: Mon May 02, 2022 1:00 pm
by answerhappygod
Thermal diffusion process is being used on a p-type base Si
wafer of 1017 cm-3 background acceptor concentration (NB) in
fabrication a Si p-n junction solar cell. The requirement is to
form an n-type emitter doped with phosphorous resulting in
concentration NS= 1019 cm-3. For this purpose, the drive-in
diffusion step is being done at 1150°C for 20 min. Determine,
(i) How much dose of the phosphorous atoms should the process
engineer realize in the pre- deposition (solubility limited
diffusion) step. Given for the phosphorous diffusion EA=3.69 eV and
D0 is 10.5 cm2s-1.
(ii) Calculate the junction depth obtained after this drive-in
diffusion.