Defects and Disorders in Semiconductors

Defects and Disorders in Semiconductors Jermell Powell ECE 423 11/15/06

Defect types • Point defects • Line defects • Area defects • Cluster defects

Point defects • Types • Frenkel defect pair

Line defects • Example

Wide defects • Area defect • Epitaxial mound • Cluster defect • Dust particle • Mask scratch

Defect density • d(r) = d{1 + 2.5 exp [0.34 X 19(1 - r/R)]}

Causes of defects • Semiconductor doping • Czochralski method

Advanced defects • Antisite • Nonstoichiometric • Void defects

Divacancy • Cause • Effect • V-V + Isi -> V-V + Isi • V-V + Isi -> V • V-V + 2Isi -> V-V + 2Isi • V-V + 2Isi -> V + Isi • V-V + 2Isi -> 0

Results • Positive • Oxygen in Silicon • Lifetimes • Diffusion lengths • Mobilities • Solar cells, IC

ZnTe and CdTe • Chlorine doping • Copper doping • GaAs, Arsenic heavy

Detrimental • Categories of Inoperability • Oxygen in Silicon • Dielectric breakdown

Questions? • Thank you