Buffer Related Dispersive Effects in Microwave GaN HEMTs

↓ Direkt till sidans innehåll
↓ Direkt till sidans sekundära innehåll (sidomenyn)

Search: id:"swepub:oai:research.chalmers.se:5b0b1d03-fbbb-46f9-933c-0f311278b7d5" > Buffer Related Disp...

1 of 1
Previous record
Next record
To hitlist

Buffer Related Dispersive Effects in Microwave GaN HEMTs

Bergsten, Johan (author): Chalmers tekniska högskola,Chalmers University of Technology

(creator_code:org_t)

ISBN 9789175977263
Gothenburg, 2018
English.

Related links:: https://research.cha... (primary) (free); show more...; https://research.cha...; show less...

Doctoral thesis (other academic/artistic)

Abstract Subject headings

In applications such as mobile communication and radar, microwave power generation at high frequency is of utmost importance. The GaN HEMT offers a unique set of properties that makes it suitable for high power amplification at high frequencies. However, their performance is limited by trap states, leading to reduced output power and time variant effects. Furthermore, for good high frequency performance a high efficiency it is essential to limit the access resistances in the transistor. The GaN HEMT technology has long lacked a good ohmic contact with good reproducibility. In this thesis, three buffer designs are considered; C-doped GaN, AlGaN back barriers and a thin GaN structure. The three designs are evaluated in terms of trapping effects using the drain current transient technique. For the C-doped GaN buffer, trapping at dislocations covered with C-clusters is believed to be the main factor limiting output power. Dislocations are presumed to play a major role for the trapping behavior of AlGaN back barriers and the thin structure as well. The maximum output powers for C-doped GaN, AlGaN back barriers and the thin structure are 3.3, 2.7, and 3.9 W/mm at 30 GHz. The output power is found to be limited by trapping effects for all buffer designs. Moreover, a Ta-based, recessed ohmic contact enables a contact resistance of down to 0.14 Ωmm. The results also indicate that a highly reproducible process might be possible for deeply recessed contacts. An optimized AlGaN/GaN interface shows high mobility \textgreater2000 cm2/Vs without the use of an AlN-exclusion layer. The improved interface also decreases trapping effects and the gate-source capacitance at large electric fields compared to an unoptimized interface.

Subject headings

NATURVETENSKAP -- Data- och informationsvetenskap -- Datorteknik (hsv//swe)
NATURAL SCIENCES -- Computer and Information Sciences -- Computer Engineering (hsv//eng)
TEKNIK OCH TEKNOLOGIER -- Maskinteknik -- Rymd- och flygteknik (hsv//swe)
ENGINEERING AND TECHNOLOGY -- Mechanical Engineering -- Aerospace Engineering (hsv//eng)
TEKNIK OCH TEKNOLOGIER -- Elektroteknik och elektronik -- Annan elektroteknik och elektronik (hsv//swe)
ENGINEERING AND TECHNOLOGY -- Electrical Engineering, Electronic Engineering, Information Engineering -- Other Electrical Engineering, Electronic Engineering, Information Engineering (hsv//eng)

Keyword

trapping effects
C-doping
AlGaN/GaN interface quality
recessed ohmic contacts
GaN HEMT
buffer design

Publication and Content Type

dok (subject category)
vet (subject category)

Find in a library

Buffer Related Dispersive Effects in Microwave GaN HEMTs (Search the publication in LIBRIS)

To the university's database

1 of 1
Previous record
Next record
To hitlist

Find more in SwePub

By the author/editor: Bergsten, Johan

About the subject

NATURAL SCIENCES: NATURAL SCIENCES; and Computer and Inf ...; and Computer Enginee ...

ENGINEERING AND TECHNOLOGY: ENGINEERING AND ...; and Mechanical Engin ...; and Aerospace Engine ...

ENGINEERING AND TECHNOLOGY: ENGINEERING AND ...; and Electrical Engin ...; and Other Electrical ...

By the university: Chalmers University of Technology

Search outside SwePub

Extend your search to:: Google; Google Book Search; Google Scholar

Kungliga biblioteket hanterar dina personuppgifter i enlighet med EU:s dataskyddsförordning (2018), GDPR. Läs mer om hur det funkar här.
Så här hanterar KB dina uppgifter vid användning av denna tjänst.

LIBRIS.kb.se