Mechanisms of Ohmic Contact Formation of Ti/Al-Based Metal Stacks on p-Doped 4H‑SiC

Ohmic contacts on p-doped 4H-SiC are essential for the fabrication of a wide range of power electron devices. Despite the fact that Ti/Al based ohmic contacts are routinely used for ohmic contacts on p-doped 4H-SiC, the underlying contact formation mechanisms are still not fully understood. TLM structures were fabricated, measured and analyzed to get a better understanding of the formation mechanism. SIMS analyses at the Ti3SiC2-SiC interface have shown a significant increase of the surface near Al concentration. By using numerical simulation it is shown that this additional surface near Al concentration is essential for the ohmic contact formation.

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Ohmic Contact Formation Mechanism of Pd-based Contact to p-GaN

MRS Proceedings ◽

10.1557/proc-622-t6.31.1 ◽

2000 ◽

Vol 622 ◽

Author(s):

Dae-Woo Kim ◽

Joon Cheol Bae ◽

Woo Jin Kim ◽

Hong Koo Baik ◽

Chong Cook Kim ◽

...

Keyword(s):

Schottky Barrier ◽

Barrier Height ◽

Formation Mechanism ◽

Ohmic Contact ◽

Room Temperature ◽

Schottky Barrier Height ◽

Contact Formation ◽

Ohmic Behavior ◽

Plane Direction ◽

Ohmic Contact Formation

ABSTRACTWe have investigated surface treatment effect on the interfacial reaction of Pd/p-GaN interface and also room temperature ohmic contact formation mechanism of Pd-based ohmic contact. In order to examine room temperature ohmic behavior, various metal contact systems were deposited and current-voltage measurements were carried out. In spite of large theoretical Schottky barrier height between Pd and p-GaN, Pd-based contact showed perfect ohmic characteristic even before annealing. According to the results of synchrotron X-ray radiation, the closed-packed atomic planes (111) of the Pd film were quite well ordered in surface normal direction as well as in the in-plane direction. The effective Schottky barrier height of Au/Pd/Mg/Pd/p-GaN was 0.47eV, which was estimated by Norde method. This discrepancy between theoretical barrier height and the measured one might be due to the epitaxial growth of Pd contact metal and so the room-temperature ohmic characteristic of Pd-based ohmic contact was related strongly to the in-plane epitaxial quality of metal on p-GaN.

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Doping and beyond: towards a common model for the ohmic contact formation mechanism in the Au/Te/Au/-, AuGe/-, and Ge/Pd/n-GaAs systems

MRS Proceedings ◽

10.1557/proc-260-355 ◽

1992 ◽

Vol 260 ◽

Author(s):

K. Wuyts ◽

J. Watté ◽

R. E. Silverans ◽

H. MüNder ◽

M. G. Berger ◽

...

Keyword(s):

Formation Mechanism ◽

Ohmic Contact ◽

Contact Formation ◽

Ohmic Contact Formation

ABSTRACTThe results of our recent research on the ohmic contact formation mechanism in furnace alloyed Au/Te/Au/GaAs contacts are summarized, and preliminary Raman measurements on annealed Ge/Pd/GaAs structures are presented. The data and those reported in literature on the AuGe- and Ge/Pd- GaAs systems are argued to be more in agreement with the graded crystalline heterojunction concept (the formation of n+-Ge/GaAs, n+Ga2Te3/GaAs junctions) than with the doping model (the formation of n+-GaAs).

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