Characterization of Trapping Effects Related to Carbon Doping Level in AlGaN Back-Barriers for AlGaN/GaN HEMTs

Funding Agencies|Competence Center for III-Nitride Technology C3NiT-Janzn
The impact of different carbon concentrations in the Al 0.06 Ga 0.94 N graded back-barrier and GaN buffer of high electron mobility transistors (HEMTs) is investigated. Four epi-wafers with different carbon concentrations, ranging from 1 x 10(17) to 5 x 10(17) cm( -3) , were grown by metal organic chemical vapor deposition (MOCVD). HEMTs with 100 and 200 nm gate lengths were fabricated and characterized with dc, Pulsed-IV, drain current transient spectroscopy (DCTS), and large-signal measurements at 30 GHz. It is shown that the back-barrier effectively prevents buffer-related electron trapping. The highest C-doping provides the best 2DEG confinement, while lower carbon doping levels are beneficial for a high output power and efficiency. A C-doping of 1 x 10(17)cm( -3) offers the highest output power at maximum power added efficiency (PAE) (1.8 W/mm), whereas 3 x 10(17) cm( -3) doping provides the highest PAE ( > 40%). The C-profiles acquired by using secondary ion mass spectroscopy (SIMS), in combination with DCTS, is used to explain the electron trapping effects. Traps associated with the C-doping in the back-barrier are identified and the bias ranges for the trap activation are discussed. The study shows the importance of considering the C-doping level in the back-barrier of microwave GaN HEMTs for power amplification and generation.

NATURVETENSKAP Fysik Den kondenserade materiens fysik hsv//swe
NATURAL SCIENCES Physical Sciences Condensed Matter Physics hsv//eng
MODFETs; HEMTs; Electrons; Logic gates; Wide band gap semiconductors; Aluminum gallium nitride; Epitaxial growth; AlGaN/GaN; back-barrier; dispersion; double heterostructure; high electron mobility transistors (HEMTs); short channel effect (SCE)

Chen, Ding-YuanSweGaN AB, S-58278 Linkoping, Sweden (author)
Chen, Jr-TaiSweGaN AB, S-58278 Linkoping, Sweden (author)
Thorsell, MattiasChalmers Univ Technol, Sweden; SAAB AB, Sweden (author)
Darakchieva, VanyaLinköpings universitet,Halvledarmaterial,Tekniska fakulteten,Lund Univ, Sweden(Swepub:liu)vanda79 (author)
Rorsman, NiklasChalmers Univ Technol, Sweden (author)
Chalmers Univ Technol, SwedenSweGaN AB, S-58278 Linkoping, Sweden (creator_code:org_t)

In:IEEE Transactions on Electron Devices: IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC0018-93831557-9646

By the author/editor: Del Castillo, Ra ...; Chen, Ding-Yuan; Chen, Jr-Tai; Thorsell, Mattia ...; Darakchieva, Van ...; Rorsman, Niklas

About the subject

NATURAL SCIENCES: NATURAL SCIENCES; and Physical Science ...; and Condensed Matter ...

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