Dry etching and metallization schemes in a GaN/SiC heterojunction device process

• Dry etching and metallization schemes are described for a GaN/SiC heterojunction. GaN was reactive ion etched in a chlorine based chemistry (Cl2/Ar), and an ICP etch was used on 4H-SiC using a fluorine based chemistry (SF6/Ar/O2). The etch rates obtained on GaN was above 400 nm/min. High sample temperature from self heating and large dc-bias was the probable cause for the high etch rate. The ICP etch rate on SiC approached 320 nm/min, and the etch selectivity to GaN was >100. The metallization was based on Ti for both n-GaN and p-SiC. TLM and Kelvin structures were used to extract the specific contact resistivity, ρC. After a 950 °C anneal in N2 ρC on the GaN samples were below 1·10-6 Ωcm2 for sputtered contacts in room temperature, and an order of magnitude higher with evaporation. On p-SiC no ohmic behavior was found with a doping of 4·1018 cm-3, but the same contact metallization on highly doped areas (>1020 cm-3) showed ohmic behavior with ρC below 10-4 Ωcm2.

Ämnesord

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)

Nyckelord

Chlorine

Dry etching

Electric contacts

Fluorine

Metallizing

Nitrides

Plasma etching

Reactive ion etching

Semiconducting gallium compounds

Semiconducting silicon compounds

Silicon carbide

Sputter deposition

Etch selectivity

Gallium nitride

Heterojunctions

Publikations- och innehållstyp

ref (ämneskategori)

art (ämneskategori)