Tunneling behavior of extremely low resistance nonalloyed Ti/Pt/Au contacts ton(p)‐InGaAs andn‐InAs/InGaAs
作者:
G. Stareev,
H. Ku¨nzel,
期刊:
Journal of Applied Physics
(AIP Available online 1993)
卷期:
Volume 74,
issue 12
页码: 7592-7595
ISSN:0021-8979
年代: 1993
DOI:10.1063/1.354986
出版商: AIP
数据来源: AIP
摘要:
Extremely low resistance nonalloyed Ti/Pt/Au contacts have been formed ton‐InGaAs,p‐InGaAs, andn‐InAs/InGaAs layers with doping concentrations ranging from 1 to 5×1019cm−3forn‐type and from 2 to 1×1020cm−3forp‐type material. The comparative studies reveal specific contact resistances as low as 1.7×10−8&OHgr; cm2for then‐InAs/InGaAs system, while the best values obtained forn‐InGaAs andp‐InGaAs are 4.3 and 4.8×10−8&OHgr; cm2, respectively. The electrical behavior of the contacts is discussed in relation to the effect of ion beam cleaning and post‐deposition annealing. The use of low energy (60 eV) Ar+bombardment provides atomically clean, contamination free surfaces. Very rapid thermal processing at 400 °C for 1 s was successfully employed in order to restore the original properties of the subsurface layer disordered during ion bombardment. This fabrication sequence ensures formation of intimate contacts without interfacial films and carrier compensation effects. The variation of the specific contact resistance with the reciprocal square root of the carrier concentration indicates that tunneling is the dominant mechanism of current flow through the metal‐semiconductor junction. The tunneling origin of the contact characteristics has also been elucidated from the temperature dependence of the contact resistance.
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