Comparison of Pd/Ge/Pd/Ti/Au and Pd/Ge/Ti/Pt ohmic contacts to n-type InGaAs

Kim, Il-Ho

doi:10.1016/s0167-577x(03)00261-1

Cited by 9 publications

(4 citation statements)

References 13 publications

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“…As shown in table 2, when the doping level is low (1.3×10 18 cm −3 ), the specific contact resistance is 8.7×10 −7 Ω cm 2 after RTA at 300 °C, 20 s. Extending the RTA time to 60 s does not improve the results, which are in fact a factor of 2 larger. For this reason, we decided to fix our alloying times to 20 s [26,35]. When the doping level is 2.5×10 18 cm −3 , the results are much better: sample d (30/ 60 nm) has a specific contact resistance value as low as 1.5×10 −7 Ω cm 2 , whilst sample c (50/100 nm) reaches virtually the same value (1.7×10 −7 Ω cm 2 ).…”

Section: Resultsmentioning

confidence: 99%

Comparison of Ti/Pd/Ag, Pd/Ti/Pd/Ag and Pd/Ge/Ti/Pd/Ag contacts to n-type GaAs for electronic devices handling high current densities

Huo

Galiana

2017

Semicond. Sci. Technol.

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In the quest for metal contacts for electronic devices handling high current densities, we report the results of Pd/Ti/Pd/Ag and Pd/Ge/Ti/Pd/Ag contacts to n-GaAs and compare them to Ti/ Pd/Ag and AuGe/Ni/Au. These metal systems have been designed with the goal of producing an electrical contact with (a) low metal-semiconductor specific contact resistance, (b) very high sheet conductance, (c) good bondability, (d) long-term durability and (e) cost-effectiveness. The structure of the contacts consists of an interfacial layer (either Pd or Pd/Ge) intended to produce a low metal-semiconductor specific contact resistance; a diffusion barrier (Ti/Pd) and a thick top layer of Ag to provide the desired high sheet conductance, limited cost and good bondability. The results show that both systems can achieve very low metal resistivity (PM ~2X 10~6 Í1 cm), reaching values close to that of pure bulk silver. This fact is attributed to the Ti/Pd bilayer acting as an efficient diffusion barrier, and thus the metal sheet resistance can be controlled by the thickness of the deposited silver layer. Moreover, the use of Pd as interfacial layer produces contacts with moderate specific contact resistance (p c ~ 10~ Í1 cm) whilst the use of Pd/Ge decreases the specific contact resistance to p c ~ 1.5 x 10~7 CI cm 2 , as a result of the formation of a Pd 4 (GaAs, Ge 2) compound at the GaAs interface.

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Section: Resultsmentioning

confidence: 99%

Comparison of Ti/Pd/Ag, Pd/Ti/Pd/Ag and Pd/Ge/Ti/Pd/Ag contacts to n-type GaAs for electronic devices handling high current densities

Huo

Galiana

2017

Semicond. Sci. Technol.

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“…These values are a record low, significantly lower than previous SPRbased contacts reported in the literature. Reasons for this include the change from a 1-step rapid thermal anneal process used in recent literature 10,11 to a 2-step rapid thermal anneal process and the exploration of Pd/Si ratios in the contact structure. The formation of the Pd-rich quaternary phase is a low activation energy process due to its observed formation as deposited, with the Pd diffusion activation energy in GaAs of only 0.35 eV calculated by Yeh et al 28 Pd 2 Si formation is a higher activation energy process, calculated as 0.9 eV by Cheung et al 29 Because of this situation, the 2-step anneal process should promote each step in series rather than in parallel as with a 1-step anneal process.…”

Section: Resultsmentioning

confidence: 99%

“…Kim et al have performed some of the most recent work on SPR contacts, demonstrating specific contact resistance values as low as 1:1 Â 10 À6 X cm 2 for a Pd/Ge SPR contact, and 3:7 Â 10 À7 X cm 2 using a Pd/Si contact assumed to form through the SPR mechanism, both on 10 19 cm À3 -doped Si : In 0:5 Ga 0:5 As. 10,11 Significant work on non-SPR contacts to heavily doped n-InGaAs has already been performed with very good results. [12][13][14] However, one of the key advantages of the SPR process is its ability to incorporate dopants into an otherwise lightly or undoped layer.…”

Section: Introductionmentioning

confidence: 99%

Ultra low-resistance palladium silicide Ohmic contacts to lightly doped n-InGaAs

Yearsley

Lin

Hwang

et al. 2012

Journal of Applied Physics

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The formation of shallow, ultra-low resistance, Pd/Si solid-phase regrowth (SPR) ohmic contacts to n À In 0:53 Ga 0:47 As epilayers of N D ¼ 1 Â 10 17 cm À3 and N D ¼ 3 Â 10 19 cm À3 is demonstrated. The resulting specific contact resistances of 9 Â 10 À8 X cm 2 and 1:8 Â 10 À8 X cm 2 , respectively, are the lowest demonstrated for SPR contacts to n-InGaAs. An optimum Pd/Si atomic ratio of 1.5 is found to be essential to achieving low specific contact resistance. A low-temperature, two-step, rapid thermal annealing process has been employed to activate the InGaAs regrowth process and consistently achieve shallow contacts with minimal lateral diffusion. Transmission electron microscopy is used to substantiate the SPR mechanism of contact formation. For lightly doped epilayers, I-V-T measurements from 77-300 K show that the ohmic behavior is a direct result of the SPR process due to the introduction of excess Si dopant greater than 10 19 cm À3 at the regrown InGaAs interface. V

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“…Because Ga has a higher solubility in Au, at the same time Au and Ge are easy to shrink and Synechococcus [7], so the out-diffusion of Sb and in-diffusion of Au are very serious for n-GaSb metallization process in case of high annealing temperatures. This leads to roughened contact surface, the indiffusion and decomposition also leads to nonuniform current flow and degrade the contact structure, resulting in vertical interface peak and affecting the reliability of the device [8]. These phenomena will make the subsequent packaging process difficult.…”

Section: Contact Mechanismsmentioning

confidence: 99%

The Ohmic contact of n-GaSb with a Mo diffusion barrier

Wang

Liu

et al. 2011

2011 Academic International Symposium on Optoelectronics and Microelectronics Technology

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Ohmic contacts to n-type GaSb have been investigated. Some drawbacks are associated with conventional Ni/AuGe/Au Ohmic contact of n-GaSb, so we propose to add a Mo diffusion barrier between AuGeNi and Au layer and carry out the structure fabrication experiment. The results show that the new metallization decreases the specific contact resistance and can be annealed at wide temperature range. It is more important that the introduction of Mo inhibits effectively the in-diffusion of atoms by the analysis of AES. It also makes the new metallization have a better surface morphology, wider temperature range and benefit for the stability of the devices.

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Comparison of Pd/Ge/Pd/Ti/Au and Pd/Ge/Ti/Pt ohmic contacts to n-type InGaAs

Cited by 9 publications

References 13 publications

Comparison of Ti/Pd/Ag, Pd/Ti/Pd/Ag and Pd/Ge/Ti/Pd/Ag contacts to n-type GaAs for electronic devices handling high current densities

Comparison of Ti/Pd/Ag, Pd/Ti/Pd/Ag and Pd/Ge/Ti/Pd/Ag contacts to n-type GaAs for electronic devices handling high current densities

Ultra low-resistance palladium silicide Ohmic contacts to lightly doped n-InGaAs

The Ohmic contact of n-GaSb with a Mo diffusion barrier

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