Low-forward-voltage-drop 4H-SiC BJTs without base contact implantation
2008 (English)In: IEEE Transactions on Electron Devices, ISSN 0018-9383, Vol. 55, no 8, 1907-1911 p.Article in journal (Refereed) Published
Bipolar junction transistors (BJTs) of 4H-SiC, with a low collector--emitter forward voltage drop YCE, have been fabricated without base contact implantation. A comparison of BJTs on the same wafer with and without base contact implantation shows less than 10% higher VcE for the BJTs without base contact implantation. Omitting the base contact implantation eliminates high concentrations of implantation-induced defects that act as recombination centers. This is advantageous because it allows a shorter distance Wp+ between the emitter edge and the base contact, without affecting the current gain when no base contact implantation is used. The BJTs without contact implantation show a constant current gain as Wp+ was reduced from 3 to I pm, whereas the gain decreased by 45% for the BJTs with base contact implantation for the same reduction of Wp+. A key to the successful fabrication of low-forward-voltage-drop SiC BJTs without base contact implantation is the formation of low-resistivity Ni/Ti/Al ohmic contacts to the base. The contact resistivity on the base region (N-A approximate to 4 x 10(17) cm(-3)) was measured with linear transmission line method structures to PC = 1.9 X 10(-3) Omega cm(2), whereas the contact resistivity with the base contact implantation was PC = 1.3 x 10-4 Omega cm(2), both after rapid thermal processing annealing at 800 degrees C.
Place, publisher, year, edition, pages
2008. Vol. 55, no 8, 1907-1911 p.
bipolar junction transistor (BJT), emitter injection efficiency, forward voltage drop, ohmic contact, 4H-silicon carbide, ohmic contacts, al/ti
Electrical Engineering, Electronic Engineering, Information Engineering
IdentifiersURN: urn:nbn:se:kth:diva-17722DOI: 10.1109/ted.2008.926641ISI: 000257950300020ScopusID: 2-s2.0-49249099302OAI: oai:DiVA.org:kth-17722DiVA: diva2:335767
QC 201005252010-08-052010-08-052010-08-19Bibliographically approved