Development of Low Resistance Al/Ti Stacked Metal Contacts to p-Type 4H-SiC

2007 ◽  
Vol 556-557 ◽  
pp. 697-700 ◽  
Author(s):  
Michael R. Jennings ◽  
Amador Pérez-Tomás ◽  
D. Walker ◽  
Lin Zhu ◽  
Peter A. Losee ◽  
...  

In this work, we have investigated triple and innovative multiple stacked contacts onto ptype SiC in order to evaluate whether or not there is any improvement in morphology or specific contact resistivity. The stacked metal contacts are based on Al, Ti and Ni with the specific contact resistivity measured at a low value of 5.02×10-6'cm2 for an Al(100 nm)/Ti(100 nm)/Al(10 nm) (where a “/” indicates the deposition sequence) triple stacked metal contact. XRD microstructural analysis and SEM measurements have been carried out and it has been discovered that the contacts, which formed the compound Ti3SiC2 at the metal/SiC interface, more readily display low-resistance ohmic characteristics after a post deposition anneal. Although the same amount of Ti (100 nm in total) has been deposited closer to the metal/SiC interface, none of the multiple stacked structures displayed ohmic behaviour after a post deposition anneal.

1997 ◽  
Vol 468 ◽  
Author(s):  
Taek Kim ◽  
Jinseok Khim ◽  
Suhee Chae ◽  
Taeil Kim

ABSTRACTWe report the low resistance ohmic contacts to p-GaN using a Pd/Au bimetal scheme. A specific contact resistivity of 9.1 × 10-3 Ω-cm2 was obtained after annealing. The metallization was e-beam evaporated on 2 μm-thick p-GaN (∼ 9 × 1016/cm3) layers grown on c-plane sapphire substrates by metalorganic chemical vapor deposition (MOCVD). The comparison with other contacts showed that the contact resistivity of the Pd/Au contacts was at least one order smaller than those of Pt/Au and Ni/Au contacts.


Author(s):  
Ying Wu ◽  
Wei Wang ◽  
Saeid Masudy-Panah ◽  
Yang Li ◽  
Kaizhen Han ◽  
...  

1999 ◽  
Vol 595 ◽  
Author(s):  
Mi-Ran Park ◽  
Wayne A. Anderson ◽  
Seong-Ju Park

AbstractA low resistance Ohmic contact to p-type GaN is essential for reliable operation of electronic and optoelectronic devices. Such contacts have been made using Ni/Au and Pd / Au contacts to p-type Mg-doped GaN (1.41×1017 cm−3) grown by metalorganic chemical vapor deposition ( MOCVD ) on ( 0001 ) sapphire substrates. Thermal evaporation was used for the deposition of those metals followed by annealing at temperatures of 400 ∼ 700 °C in an oxygen and nitrogen mixed gas ambient, then subsequently cooled in liquid nitrogen which reduced the specific contact resistance from the range of 9.46∼2.80×10−2 ωcm2 to 9.84∼2.65×10−4 ωcm2 for Ni/Au and from the range of 8.35∼5.01×10−4 ωcm2 to 3.34∼1.80×10−4 ωcm2 for Pd/Au. The electrical characteristics for the contacts were examined by the current versus voltage curves and the specific contact resistance was determined by use of the circular transmission line method (c-TLM). The effects of the cryogenic process on improving Ohmic behavior (I-V linearity) and reducing the specific contact resistance will be discussed from a microstructural analysis which reveals the metallurgy of Ohmic contact formation.


2000 ◽  
Vol 5 (S1) ◽  
pp. 901-907
Author(s):  
Mi-Ran Park ◽  
Wayne A. Anderson ◽  
Seong-Ju Park

A low resistance Ohmic contact to p-type GaN is essential for reliable operation of electronic and optoelectronic devices. Such contacts have been made using Ni/Au and Pd / Au contacts to p-type Mg-doped GaN (1.41×1017 cm−3) grown by metalorganic chemical vapor deposition ( MOCVD ) on ( 0001 ) sapphire substrates. Thermal evaporation was used for the deposition of those metals followed by annealing at temperatures of 400 ∼ 700 °C in an oxygen and nitrogen mixed gas ambient, then subsequently cooled in liquid nitrogen which reduced the specific contact resistance from the range of 9.46∼2.80×10−2 Ωcm2 to 9.84∼2.65×10−4 Ωcm2 for Ni/Au and from the range of 8.35∼5.01×10−4 Ωcm2 to 3.34∼1.80×10−4 Ωcm2 for Pd/Au. The electrical characteristics for the contacts were examined by the current versus voltage curves and the specific contact resistance was determined by use of the circular transmission line method (c-TLM). The effects of the cryogenic process on improving Ohmic behavior (I-V linearity) and reducing the specific contact resistance will be discussed from a microstructural analysis which reveals the metallurgy of Ohmic contact formation.


2014 ◽  
Vol 778-780 ◽  
pp. 681-684 ◽  
Author(s):  
Katarina Smedfors ◽  
Luigia Lanni ◽  
Mikael Östling ◽  
Carl Mikael Zetterling

Extreme temperature measurements of Ni/Ti/Al contacts to p-type SiC (Na= 1∙1018cm-3), with a specific contact resistivity ρc= 6.75∙10-4Ωcm2at 25 °C, showed a five time increase of the specific contact resistivity at -40 °C (ρc= 3.16∙10-3Ωcm2), and a reduction by almost a factor 10 at 500 °C (ρc= 7.49∙10-5Ωcm2). The same response of ρcto temperature was seen for contacts on lower doped epitaxial layer. Also N-type nickel contacts improved with higher operational temperature but with a considerably smaller variation over the same temperature interval. No degradation of the performance was seen to either the Ni/Ti/Al or the Ni contacts due to the high temperature measurements.


2015 ◽  
Vol 28 (3) ◽  
pp. 457-464
Author(s):  
Aaron Collins ◽  
Yue Pan ◽  
Anthony Holland

We present a numerical method to extract specific contact resistivity (SCR) for three-dimensional (3-D) contact structures using a two-electrode test structure. This method was developed using Finite Element Modeling (FEM). Experimental measurements were performed for contacts of 200 nm nickel (Ni) to p+-type germanium (Ge) substrates and 200 nm of Titanium (Ti) on 4H-Silicon Carbide (SiC). The SCR obtained was (2.3-27)?10-6 ??cm2 for the Ni-Ge contacts and (1.3-2.4)?10-3 ??cm2 for the Ti-SiC.


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