NiGeAu Ohmic Contact in InGaP pHEMTs

Ellen Lan, Qianghua Xie, Peter Fejes, and Ha Le,

Motorola Inc., Semiconductor Products Sector

2100 East Elliot Road, MD EL720, Tempe, AZ 85284, USA

Phone: (480) 413-4128, Fax: (480) 413-4453, Email: ellen.lan@motorola.com

 

Keywords: InGaP/InGaAs pHEMT, ohmic contacts, NiGeAu, annealing, contact resistance, TEM

 

Abstract

NiGeAu ohmic contact as a function of alloying temperature on InGaP/InGaAs pHEMT structure was investigated. It was found that the optimum RTA condition is 460 C 60 sec for n+ contact resistance, whereas 420 C 30 sec for on-resistance. Electron microscope examinations of the cross-sectional samples annealed at these two conditions revealed three types of alloy grains. Chemical compositions of these grains were obtained by the nano-probe X-ray energy dispersive spectrum (EDS) analysis. A correlation between these alloy grains and the contact resistance and on-resistance was established.

 

 

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