Observatorio de I+D+i UPM

Memorias de investigación
Research Publications in journals:
Ti/Pd/Ag Contacts to n-Type GaAs for High Current Density Devices
Year:2016
Research Areas
  • Solar cells,
  • Technology of devices for engineering
Information
Abstract
The metallization stack Ti/Pd/Ag on n-type Si has been readily used in solar cells due to its low metal/semiconductor specific contact resistance, very high sheet conductance, bondability, long-term durability, and cost-effectiveness. In this study, the use of Ti/Pd/Ag metallization on n-type GaAs is examined, targeting electronic devices that need to handle high current densities and with grid-like contacts with limited surface coverage (i.e., solar cells, lasers, or light emitting diodes). Ti/Pd/Ag (50 nm/50 nm/1000 nm) metal layers were deposited on n-type GaAs by electron beam evaporation and the contact quality was assessed for different doping levels (from 1.3 × 1018 cm?3 to 1.6 × 1019 cm?3) and annealing temperatures (from 300°C to 750°C). The metal/semiconductor specific contact resistance, metal resistivity, and the morphology of the contacts were studied. The results show that samples doped in the range of 1018 cm?3 had Schottky-like I?V characteristics and only samples doped 1.6 × 1019 cm?3 exhibited ohmic behavior even before annealing. For the ohmic contacts, increasing annealing temperature causes a decrease in the specific contact resistance (? c,Ti/Pd/Ag ~ 5 × 10?4 ? cm2). In regard to the metal resistivity, Ti/Pd/Ag metallization presents a very good metal conductivity for samples treated below 500°C (? M,Ti/Pd/Ag ~ 2.3 × 10?6 ? cm); however, for samples treated at 750°C, metal resistivity is strongly degraded due to morphological degradation and contamination in the silver overlayer. As compared to the classic AuGe/Ni/Au metal system, the Ti/Pd/Ag system shows higher metal/semiconductor specific contact resistance and one order of magnitude lower metal resistivity.
International
Si
JCR
Si
Title
Journal of Electronic Materials
ISBN
0361-5235
Impact factor JCR
1,491
Impact info
Volume
45
10.1007/s11664-016-4432-6
Journal number
6
From page
2769
To page
2775
Month
SIN MES
Ranking
Participants
  • Autor: Ignacio Rey-Stolle Prado (UPM)
Research Group, Departaments and Institutes related
  • Creador: Centro o Instituto I+D+i: Instituto de Energía Solar
S2i 2020 Observatorio de investigación @ UPM con la colaboración del Consejo Social UPM
Cofinanciación del MINECO en el marco del Programa INNCIDE 2011 (OTR-2011-0236)
Cofinanciación del MINECO en el marco del Programa INNPACTO (IPT-020000-2010-22)