Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Processing and characterization of silicon carbide (6H-SiC and 4H-SiC) contacts for high power and high temperature device applications
KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
2002 (English)Doctoral thesis, comprehensive summary (Other scientific)
Abstract [en]

Silicon carbide is a promising wide bandgap semiconductormaterial for high-temperature, high-power, and high-frequencydevice applications. However, there are still a number offactors that are limiting the device performance. Among them,one of the most important and critical factors is the formationof low resistivity Ohmic contacts and high-temperature stableSchottky diodes on silicon carbide.

In this thesis, different metals (TiW, Ti, TiC, Al, and Ni)and different deposition techniques (sputtering andevaporation) were suggested and investigated for this purpose.Both electrical and material characterizations were performedusing various techniques, such as I-V, C-V, RBS, XRD, XPS,LEED, SEM, AFM, and SIMS.

For the Schottky contacts to n- and p-type 4H-SiC, sputteredTiW Schottky contacts had excellent rectifying behavior afterannealing at 500 ºC in vacuum with a thermally stableideality factor of 1.06 and 1.08 for n- and p-type,respectively. It was also observed that the SBH for p-type SiC(ΦBp) strongly depends on the choice the metal with alinear relationship ΦBp= 4.51 - 0.58Φm, indicating no strong Fermi-level pinning.Finally, the behavior of Schottky diodes was investigated byincorporation of size-selected Au nano-particles in Ti Schottkycontacts on silicon carbide. The reduction of the SBH isexplained by using a simple dipole layer approach, withenhanced electric field at the interface due to the small sizeof the circular patch (Au nano-particles) and large differenceof the barrier height between two metals (Ti and Au) on both n-and p-SiC.

For the Ohmic contacts, titanium carbide (TiC) was used ascontacts to both n- and p-type 4H-SiC epilayers as well as onAl implanted layers. The TiC contacts were epitaxiallydeposited using a co-evaporation method with an e-beam Tisource and a Knudsen cell for C60, in a UHV system at low substrate temperature(500 ºC). In addition, we extensively investigatedsputtered TiW (weight ratio 30:70) as well as evaporated NiOhmic contacts on both n- and p-type epilayers of SiC. The bestOhmic contacts to n-type SiC are annealed Ni (>950ºC)with the specific contact resistance of ≈ 8× 10-6Ω cm2with doping concentration of 1.1 × 10-19cm-3while annealed TiW and TiC contacts are thepreferred contacts to p-type SiC. From long-term reliabilitytests at high temperature (500 ºC or 600 ºC) invacuum and oxidizing (20% O2/N2) ambient, TiW contacts with a platinum cappinglayer (Pt/Ti/TiW) had stable specific contact resistances for>300 hours.

Keywords: silicon carbide, Ohmic and Schottky contacts,co-evaporation, current-voltage, capacitance-voltagemeasurement, power devices, nano-particles, Schottky barrierheight lowering, and TLM structures.

Place, publisher, year, edition, pages
Kista: Mikroelektronik och informationsteknik , 2002. , xii, 88 p.
Series
Trita-EKT, ISSN 1650-8599 ; 2002:1
Keyword [en]
Silicon carbide, ohmic and schottky contacts, co-evaporation, current-voltage, powre devices, nano-particles, Schottky barrier height lowering, TLM structures
Identifiers
URN: urn:nbn:se:kth:diva-3335ISBN: OAI: oai:DiVA.org:kth-3335DiVA: diva2:9124
Public defence
2002-05-08
Note
NR 20140805Available from: 2002-05-06 Created: 2002-05-06Bibliographically approved

Open Access in DiVA

fulltext(3170 kB)14728 downloads
File information
File name FULLTEXT01.pdfFile size 3170 kBChecksum MD5
06114fa14fd886e169f8de958969a0333ee59d2c21f8441d86aaf7c6be0991a5e7b5da7a
Type fulltextMimetype application/pdf

By organisation
Microelectronics and Information Technology, IMIT

Search outside of DiVA

GoogleGoogle Scholar
Total: 14728 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

urn-nbn

Altmetric score

urn-nbn
Total: 1155 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf