Effect of layer thickness on device response of silicon heavily supersaturated with sulfur

Journal Article · Sun May 15 00:00:00 EDT 2016 · AIP Advances

DOI:https://doi.org/10.1063/1.4948986· OSTI ID:22611720

Hutchinson, David ^[1]; Mathews, Jay ^[2]; Sullivan, Joseph T.; Buonassisi, Tonio ^[3]; Akey, Austin ^[3]; Aziz, Michael J. ^[4]; Persans, Peter ^[1]

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1. Department of Physics, Applied Physics, and Astronomy, Rensselaer Polytechnic Institute, Troy NY 12180 (United States)
2. US Army ARDEC – Benét Laboratories, Watervliet NY 12189 (United States)
3. School of Engineering, Massachusetts Institute of Technology, Cambridge MA 02139 (United States)
4. Harvard John A. Paulson School of Engineering and Applied Sciences, Cambridge MA 02138 (United States)

We report on a simple experiment in which the thickness of a hyperdoped silicon layer, supersaturated with sulfur by ion implantation followed by pulsed laser melting and rapid solidification, is systematically varied at constant average sulfur concentration, by varying the implantation energy, dose, and laser fluence. Contacts are deposited and the external quantum efficiency (EQE) is measured for visible wavelengths. We posit that the sulfur layer primarily absorbs light but contributes negligible photocurrent, and we seek to support this by analyzing the EQE data for the different layer thicknesses in two interlocking ways. In the first, we use the measured concentration depth profiles to obtain the approximate layer thicknesses, and, for each wavelength, fit the EQE vs. layer thickness curve to obtain the absorption coefficient of hyperdoped silicon for that wavelength. Comparison to literature values for the hyperdoped silicon absorption coefficients [S.H. Pan et al. Applied Physics Letters 98, 121913 (2011)] shows good agreement. Next, we essentially run this process in reverse; we fit with Beer’s law the curves of EQE vs. hyperdoped silicon absorption coefficient for those wavelengths that are primarily absorbed in the hyperdoped silicon layer, and find that the layer thicknesses obtained from the fit are in good agreement with the original values obtained from the depth profiles. We conclude that the data support our interpretation of the hyperdoped silicon layer as providing negligible photocurrent at high S concentrations. This work validates the absorption data of Pan et al. [Applied Physics Letters 98, 121913 (2011)], and is consistent with reports of short mobility-lifetime products in hyperdoped layers. It suggests that for optoelectronic devices containing hyperdoped layers, the most important contribution to the above band gap photoresponse may be due to photons absorbed below the hyperdoped layer.

• OSTI ID: 22611720
• Journal Information: AIP Advances, Vol. 6, Issue 5; Other Information: (c) 2016 Author(s); Country of input: International Atomic Energy Agency (IAEA); ISSN 2158-3226
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ABSORPTION
APPROXIMATIONS
COMPARATIVE EVALUATIONS
CONCENTRATION RATIO
ION IMPLANTATION
IONS
LASER RADIATION
LAYERS
LIFETIME
MELTING
MOBILITY
OPTOELECTRONIC DEVICES
PHOTOCURRENTS
PHOTONS
QUANTUM EFFICIENCY
SILICON
SOLIDIFICATION
SULFUR ADDITIONS
THICKNESS
VISIBLE RADIATION