Photo-thermal Processing of Semiconductor Fibers and Thin Films

Author

Nishant Gupta, Clemson UniversityFollow

Date of Award

12-2012

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Legacy Department

Electrical Engineering

Committee Chair/Advisor

Singh, Rajendra

Committee Member

Bridgwood , Michael A

Committee Member

Harrell , William R

Committee Member

Grujicic , Mica

Abstract

Furnace processing and rapid thermal processing (RTP) have been an integral part of several processing steps in semiconductor manufacturing. The performance of RTP techniques can be improved many times by exploiting quantum photo-effects of UV and vacuum ultraviolet (VUV) photons in thermal processing and this technique is known as rapid photo-thermal processing (RPP). As compared to furnace processing and RTP, RPP provides higher diffusion coefficient, lower stress and lower microscopic defects. In this work, a custom designed automated photo assisted processing system was built from individual parts and an incoherent light source. This photo-assisted processing system is used to anneal silica clad silicon fibers and deposit thin-films. To the best of our knowledge, incoherent light source based rapid photo-thermal processing (RPP) was used for the first time to anneal glass-clad silicon core optical fibers. X-ray diffraction examination, Raman spectroscopy and electrical measurements showed a considerable enhancement of structural and crystalline properties of RPP treated silicon fibers. Photons in UV and vacuum ultraviolet (VUV) regions play a very important role in improving the bulk and carrier transport properties of RPP-treated silicon optical fibers, and the resultant annealing permits a path forward to in situ enhancement of the structure and properties of these new crystalline core optical fibers.
To explore further applications of RPP, thin-films of Calcium Copper Titanate (CaCu₃Ti₄O₁₂) or CCTO and Copper (I) Oxide (Cu₂O) were also deposited using photo-assisted metal-organic chemical vapor deposition (MOCVD) on Si/SiO₂ and n-Si substrate respectively. CCTO is one of the most researched giant dielectric constant materials in recent years. The given photo-assisted MOCVD approach provided polycrystalline CCTO growth on a SiO₂ surface with grain sizes as large as 410 nm. Copper (I) oxide (Cu₂O) is a direct band gap semiconductor with p-type conductivity and is a potential candidate for multi-junction solar cells. X-ray diffraction study revealed a preferred orientation, as (200) oriented crystals of Cu₂O are grown on both substrates. Also, electrical characterization of Cu₂O/n-Si devices showed the lowest saturation current density of 1.5x10-12 A/cm2 at zero bias. As a result, photo-assisted thermal processing has the potential of making the process more effective with enhanced device performance.

Recommended Citation

Gupta, Nishant, "Photo-thermal Processing of Semiconductor Fibers and Thin Films" (2012). All Dissertations. 1028.
https://open.clemson.edu/all_dissertations/1028