Electrical and structural characterisation of NiGe n-GaAs interface

✍ Scribed by L David; B Kovács; I Mojzes; B Pécz; J Lábár; L Dobos

• Publisher: Elsevier Science
• Year: 1998
• Tongue: English
• Weight: 411 KB
• Volume: 50
• Category: Article
• ISSN: 0042-207X
• DOI: 10.1016/s0042-207x(98)00071-2

✦ Synopsis

The structural and electrical behaviour of Ni/Ge layers deposited onto n-type GaAs by electron beam evaporation were studied. The samples have been annealed for 20 min at different temperatures in flowing forming gas-H 2 : N 2 (5% : 95%)-in a tube furnace. When the annealing temperature was increased the Schottky barrier heights calculated from I-V and C-V characteristics decreased, and the I-V characteristics of the samples heat treated at 600°C became linear. The contact resistance of the samples with linear characteristic was measured with Cox method. The calculated specific resistivity was 4.4×10 -4 ohmcm 2 in the case of sample heat treated at 550°C and 5.1×10 -5 ohmcm 2 after annealing at 600°C. In the sample annealed at 550°C protrusions appeared with the size of 20-30 nm at the interface of semiconductor-metal. Detectable amount of Ge was found in addition to Ni, As, and G in the protrusions. Moreover, those features contain significantly less Ga than As. The protrusions containing Ge play a role in the formation of the low barrier contact.