P Implantation Effect on Specific Contact Resistance in 3C-SiC Grown on Si

2008 ◽  
Vol 1068 ◽  
Author(s):  
Anne-Elisabeth Bazin ◽  
Jean-François Michaud ◽  
Marc Portail ◽  
Thierry Chassagne ◽  
Marcin Zielinski ◽  
...  
Keyword(s):  
Contact Resistance ◽  
Specific Contact Resistance ◽  
Transfer Length ◽  
Fourier Transformed Infrared Spectroscopy ◽  
Annealing Conditions ◽  
Device Processing ◽  
Highly Sensitive ◽  
Specific Contact ◽  
Metal Layers ◽  
Secondary Ion

ABSTRACTIn this work, non-intentionally doped 3C-SiC epilayers were implanted using phosphorus at different energies and subsequently annealed at temperatures between 1100°C and 1350°C in order to form n+ implanted layers. Different techniques such as Fourier Transformed InfraRed spectroscopy (FTIR) and Secondary Ion Mass Spectroscopy (SIMS) were used to characterize implanted 3C-SiC epilayers after the different annealing steps. Successively, metal layers were sputtered in order to form the contacts. The specific contact resistance (ñC) was determined by using circular Transfer Length Method (c-TLM) patterns. Specific contact resistance values were investigated as a function of doping and contact annealing conditions and compared to those obtained for highly doped 3C-SiC epilayers. As expected, ñC value is highly sensitive to post-implantation annealing and metal contact annealing. This work demonstrates that low resistance values can be achieved using phosphorus implantation and, hence, enabling device processing.

Ohmic Contacts to p-Type InGaAs/InP with a Graded Bandgap Heterobarrier

1993 ◽  
Vol 318 ◽  
Author(s):  
Patrick W. Leech ◽  
Geoffrey K. Reeves
Keyword(s):  
Contact Resistance ◽  
Ohmic Contacts ◽  
Rutherford Backscattering Spectrometry ◽  
Specific Contact Resistance ◽  
Superlattice Structure ◽  
Specific Contact ◽  
P Type ◽  
Metal Layers ◽  
Anneal Temperature ◽  
Graded Bandgap

ABSTRACTOhmic contacts to p-type InP with an In0.47Ga0.53As buffer layer and an interposed superlattice of 50 Å In0.47Ga0.53As/ 50 Å InP have been investigated. Initial studies of contacts to In0.47Ga0.53As/ InP without the superlattice structure have shown that Pd/Zn/Pd/Au metallization produced a lower specific contact resistance (pc = 1.1 × 10−4 Ω cm2) than Pd/Ge/Au, and over a wider range of anneal temperature than Au/Zn/Au. The incorporation of the superlattice in the p-In0.47Ga0.53As/ InP structure resulted in Pd/Zn/Pd/Au contacts with pc of 3.2 × 10−5 Ω cm2 as-deposited and 7.5 × 10−6 Ω.cm2 after a 500 °C anneal. The presence of Pd/Zn in the metallization was shown as important in reducing pc. Significant intermixing of the metal layers and In0.47Ga0.53As occured at ≥ 350 °C, as revealed by Rutherford backscattering spectrometry.

Al/Ni And Al/Ti Ohmic Contact To P-type SiC Diffused Layer

2000 ◽  
Vol 640 ◽  
Author(s):  
Xaiobin Wang ◽  
Stanislav Soloviev ◽  
Ying Gao ◽  
G. Straty ◽  
Tangali Sudarshan ◽  
...  
Keyword(s):  
Contact Resistance ◽  
Ohmic Contacts ◽  
Specific Contact Resistance ◽  
Metal Contacts ◽  
Transfer Length ◽  
Type Layer ◽  
Transmission Line Method ◽  
Specific Contact ◽  
Background Doping ◽  
P Type

ABSTRACTOhmic contacts to p-type SiC were fabricated by depositing Al/Ni and Al/Ti followed by high temperature annealing. A p-type layer was fabricated by Al or B diffusion from vapor phase into both p-type and n-type substrates. The thickness of the diffused layer was about 0.1–0.2 μm with surface carrier concentration of about 1.0×1019cm−3. Metal contacts to a p-type substrate with a background doping concentration of 1.2×1018cm−3, without a diffusion layer, were also formed. The values of specific contact resistance obtained by Circular Transmission Line Method (CTLM) and Transfer Length Method (TLM) for the n-type substrate, and by Cox & Strack method for p-type substrate, respectively, varied from 1.3×10−4Ωcm2 to 8.8×10−3 Ωcm2. The results indicate that the specific contact resistance could be significantly reduced by creating a highly doped diffused surface layer.

scholarly journals Ohmic contacts to Si-implanted and un-implanted n-type GaN

1995 ◽  
Vol 395 ◽  
Author(s):  
J. Brown ◽  
J Ramer ◽  
K. ZHeng ◽  
L.F. Lester ◽  
S.D. Hersee ◽  
...  
Keyword(s):  
Contact Resistance ◽  
Ohmic Contacts ◽  
Annealing Temperature ◽  
Contact Resistivity ◽  
Contact Structures ◽  
Specific Contact Resistance ◽  
Resistance Variation ◽  
Specific Contact ◽  
Metal Layers ◽  
Nitrogen Vacancies

ABSTRACTWe report on ohmic contacts to Si-implanted and un-implanted n-type GaN on sapphire. A ring shaped contact design avoids the need to isolate the contact structures by additional implantation or etching. Metal layers of Al and Ti/Al were investigated. On un-implanted GaN, post metalization annealing was performed in an RTA for 30 seconds in N2 at temperatures of 700, 800, and 900°C, A minimum specific contact resistance (rc) of 1.4×10−5 Ω-cm2 was measured for Ti/Al at an annealing temperature of 800°C. Although these values are reasonably low, variations of 95% in specific contact resistance were measured within a 500 µm distance on the wafer. These results are most likely caused by the presence of compensating hydrogen. Specific contact resistance variation was reduced from 95% to 10% by annealing at 900°C prior to metalization. On Si-implanted GaN, un-annealed ohmic contacts were formed with Ti/Al metalization. The implant activation anneal of 1120°C generates nitrogen vacancies that leave the surface heavily n-type, which makes un-annealed ohmic contacts with low contact resistivity possible.

Electrical Characterization of Nitrogen Implanted 3C-SiC by SSRM and C­TLM Measurements

2011 ◽  
Vol 679-680 ◽  
pp. 193-196 ◽  
Author(s):  
Xi Song ◽  
Anne Elisabeth Bazin ◽  
Jean François Michaud ◽  
Frédéric Cayrel ◽  
Marcin Zielinski ◽  
...  
Keyword(s):  
Contact Resistance ◽  
Room Temperature ◽  
Electrical Characterization ◽  
Specific Contact Resistance ◽  
Nitrogen Implantation ◽  
Transfer Length ◽  
Characterization Methods ◽  
Activation Rate ◽  
Specific Contact ◽  
Titanium Nickel

Two electrical characterization methods were used to study 3C-SiC epilayers doped by nitrogen implantation: circular Transfer Length Method (c­TLM) which allows extracting the specific contact resistance and Scanning Spreading Resistance Microscopy (SSRM) used to measure activated doping concentration. 3C-SiC samples were implanted at room temperature with different energies (ranging from 30 to 150keV) and doses (from 1 to 5.4x1015cm-2) in order to obtain a 300nm thick box-like profile at 5x1020cm-3. To activate the dopant, the samples were then annealed from 1150°C to 1350°C for 1h to 4h. Titanium-nickel c-TLM contacts annealed at 1000°C under argon showed the best results in terms of specific contact resistance (8x10-6.cm2) after a 1350°C–1h annealing. For this annealing condition, the activation rate was assessed by SSRM around 13%. This value confirms the difficulty to activate the dopants introduced into the 3C-SiC as the temperature is limited by the silicon substrate. However, this work demonstrates that low resistance values can be achieved on 3C-SiC, using nitrogen implantation at room temperature.

Highly Reliable WGe Ohmic Contact to GaAs-AlGaAs HBTs

1992 ◽  
Vol 282 ◽  
Author(s):  
T. R. Fullowan ◽  
F. Ren ◽  
B. Tseng ◽  
S. J. Pearton ◽  
C. R. Abernathy ◽  
...  
Keyword(s):  
Electrical Characterization ◽  
Specific Contact Resistance ◽  
Post Deposition Annealing ◽  
Transfer Length ◽  
Auger Analysis ◽  
Transfer Resistance ◽  
Annealing Conditions ◽  
Specific Contact ◽  
Post Deposition

ABSTRACTWe report a highly reliable, sputtered WGe emitter contact for npn heterojunction bipolartransistors. A specific contact resistance of 7.5 × 10−7 Ω-cm2 and a transfer resistance of 4.0 × 10−2 Ωmm were obtained after 380°C, 1 min alloy. The contact was patterned by SF6 dry etching at low bias using a Au mask. This novel contact has comparable resistance to conventional AuGe-based metallization while having superior thermal stability. We have studied the dependence of contact properties on the post-deposition annealing conditions by transfer length method of electrical characterization and Auger analysis, and will also report long-term reliability results in comparison to AuGe-based metallization.

Electrical Properties of (Zn, Mn) Containing Multilayer Metallizations to p-Type InGaAs/InP

1995 ◽  
Vol 382 ◽  
Author(s):  
Patrick W. Leec ◽  
Geoffrey K. Reeves ◽  
Wei Zhou
Keyword(s):  
Electrical Properties ◽  
Contact Resistance ◽  
Layer Thickness ◽  
Annealing Temperature ◽  
Specific Contact Resistance ◽  
Annealing Temperatures ◽  
Specific Contact ◽  
A Minor ◽  
P Type ◽  
Metal Layers

ABSTRACTThe specific contact resistance, pc, of Au/Zn/Au, Ni/Zn/Ni/Au, Pd/Zn/Pt/Au and Pd/Mln/Sb/Pd/Au contacts to p-In0.47Ga0.53As/ InP has been measured as a function of layer thickness of Zn or Mn. All of the as-deposited contacts were ohmic, with pc = 1−2 × 10−5 Ω cm2. Increasing thickness of the Zn layer above 200 Å in the Au/Zn/Au contacts resulted in a minor decrease in pc while producing no change in the Ni/Zn/Ni/Au metallization. For the as-deposited Pd/Mn/Pd/Au contacts, the value of pc was independent of thickness of the Mn layer but differences in pc emerged at annealing temperatures of ≥ 250°. The analysis of these structures by RBS has shown an extensive intermixing of the metal layers at an annealing temperature of 450 °. In the Pd/Zn/Pt/Au contacts, the value of pc was reduced to a minimum value of 8 × 10−6 Ω cm2 by annealing at a temperature of 500 °. An examination of the Pd/Zn/Pt/Au configuration by RBS has shown that the Pt layer acted as a barrier for the indiffusion of the Au.

The Reliability of Multilevel Metallization on InGaAs/GaAs Layers

1994 ◽  
Vol 337 ◽  
Author(s):  
Edward Y. Chang ◽  
J.S. Chen ◽  
J.W. Wu ◽  
K.C. Lin
Keyword(s):  
Contact Resistance ◽  
Ohmic Contacts ◽  
Molecular Beam ◽  
Specific Contact Resistance ◽  
Transmission Line Model ◽  
X Ray Diffraction ◽  
X Ray ◽  
Specific Contact ◽  
Secondary Ion ◽  
Contact Metal

ABSTRACTNon-alloyed ohmic contacts using Ti/Pt/Au and Ni/Ge/Au on InGaAs/GaAs layers grown by Molecular Beam Epitaxy (MBE) have been investigated. The n-type InGaAs film has a doping concentration higher than 1X1019 cm-3. Specific contact resistance below 2X10-7 Ωcm2 could be easily achieved with Ti/Pt/Au. Due to the layer intermixing and outdiffusion of In and Ga, the specific contact resistance and sheet resistance increase after thermal treatment. When Ni/Ge/Au is used as the contact metal, the outdiffusion of In and Ga atoms is more severe than that of Ti/Pt/Au. After annealing at 450°C for two minutes, the Au4In formed and the characteristics of the contact became worse. All the phenomena illustrated above have been observed and investigated by Transmission Line Model, X-ray diffraction, Auger Electron Spectroscopy and Secondary Ion Mass Spectrum. As far as the thermal stability is concerned, it is convinced that Ti/Pt/Au is the best one of these two non-alloyed ohmic contact studied.

Ohmic Contact in P-HEMT Wafer Using Metallization with Ge/Au/Ni/Au

2014 ◽  
Vol 896 ◽  
pp. 351-353
Author(s):  
Asban Dolah ◽  
Muhammad Azmi Abd Hamid ◽  
Mohamad Deraman ◽  
Ashaari Yusof ◽  
Nor Azhadi Ngah ◽  
...  
Keyword(s):  
Contact Resistance ◽  
Ohmic Contact ◽  
Specific Contact Resistance ◽  
Semiconductor Interface ◽  
Transmission Line Method ◽  
Metal Thickness ◽  
Specific Contact ◽  
Lift Off ◽  
Electrical Characterizations ◽  
Metal Layers

In this study, Ohmic contact were fabricated on AlGaAs HEMTs structure. A good metal-semiconductor interface are essentially for achieving lower specific contact resistance. An AlGaAs epi wafer was supply by the vendor. AlGaAs substrate was cleaned using wet chemical etching. Electrodes were fabricated through a sequenced of lithography, cleaning, sputtering and lift-off processes. The electrodes were made with metal layers of Ge, Au and Ni. Parameters such as metal thickness, annealing temperatures (from 300°C to 400°C) and annealing time were varies during fabrication process. Electrical characterizations after annealing are carried out using transmission line method (TLM) to obtain the specific contact resistance. Annealing temperature between 340°C to 360°C produced contact resistance below 5 x 10ˉ³Ω/cm-2.

Studing the Effect of Etching Process on the Ohmic Specific Contact Resistance of AlGaN/GaN HEMT

2021 ◽  
Vol 31.2 (149) ◽  
Keyword(s):  
Integrated Circuits ◽  
Contact Resistance ◽  
Etching Rate ◽  
Power Source ◽  
Specific Contact Resistance ◽  
Process Conditions ◽  
Transmission Method ◽  
Etching Depth ◽  
Specific Contact ◽  
Metal Layers

In electronic devices, ranging from integrated circuits to solar cells, the Ohmic specific contact resistance between metal and semiconductor is a measure of device performance. In this paper, the effect of Induction Coupled Plasma etching (ICP) on creating specific contact resistance between metals and semiconductors was investigated by linear transmission method (LTLM). The obtained results show that selecting etching depth and etch process conditions by ICP method before metal coating is a decisive step in the manufacture of low resistance Ohmic contact. The value of formed Ohmic specific contact resistance is the lowest when the etching depth ensures the metal layers to cover the doped AlGaN region at a distance of about 8nm above the AlGaN/GaN interface. With an ion power source (RIE) of 30W and a plasma power source (ICP) of 250W, the etching rate of AlGaN material is approximately 27.21 nm / minute. The Ohmic specific contact resistance of metal layers Ti (20nm) / Al (200nm) / Pd (60nm) / Au (100nm) with AlGaN semiconductor has an optimal value of ρc = 1.08 x 10-7 cm2, despite the sample was annealing at a relatively low temperature of 650oC, in a nitrogen atmosphere at 650oC.

Low Resistance Non-Transparent ohmic Pt-contacts on p-GaN

2001 ◽  
Vol 693 ◽  
Author(s):  
Andreas Weimar ◽  
Stefan Bader ◽  
Georg Brüderl ◽  
Volker Kümmler
Keyword(s):  
Contact Resistance ◽  
Ohmic Contacts ◽  
Hole Concentration ◽  
Blue Laser ◽  
Specific Contact Resistance ◽  
Low Resistance ◽  
Specific Contact ◽  
Device Operation ◽  
Secondary Ion ◽  
Resistance Value

AbstractThe metal – p-GaN junction for low resistance ohmic contacts is still a challenge to be applied in GaN-based opto electronics as well as in power and high frequency devices. Currently, we try to improve the performance of our blue laser diodes. In order to decrease heat generation during device operation it is necessary to ensure as small contact resistances as possible.In this work, we achieved a specific contact resistance value of RC = 1.8 ± 1.7. 10-5 Ωcm2 for Pt-contacts on MOVPE-grown p-GaN. The Pt-layers were deposited by e-beam and thermally assisted vacuum evaporation after a standard cleaning process. For evaluation of Rc we used optimised circular TLM test patterns defined by photolithography. Best contacts were formed by annealing in Nitrogen athmosphere at 500°C.We also investigated the dependence of the contact resistance on the Mg doping concentration. Therefore p-GaN layers with different Mg-concentrations were grown on SiC-substrates and Pt-contacts were processed. For those samples, we investigated the Mg-concentrations, verified by secondary ion mass spectroscopy (SIMS), the hole concentrations and mobilities in dependence of C(Mg), which we obtained from HALL-measurements, and the contact and sheet resistances, measured by circular TLM measurements.The experiments showed that the optimum Mg-concentration for low contact resistances is higher than 2 1019 cm-3 which was found to provide a maximum hole concentration near 7 1017 cm-3. The influence of self-compensation in p-GaN in bulk and near interfaces will be discussed.

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