Optimization of recessed ohmic contacts for AlGaN/AlN/GaN heterostructures using C(V) characterization of MSHM structures

• Recess etching is used to reduce the resistance of ohmiccontacts to an AlGaN/AlN/GaN heterostructure. Theminimization of the resistance relies on exact etching ofthe barrier. For this purpose C(V) measurements of theetched contacts, before annealing, are used to characterizethe effect of the recess etch. Using the C(V) measurementsa Cl2/Ar based ICP/RIE etch recipe with a stabilizedetch rate of approximately 3 Å/s is developed. By utilizing the recess etch the contact resistivity is reducedfrom the non etched 0.9 Ω•mm to 0.3 Ω•mm when approximately2 nm remains of the barriers, while maintaininga low sheet resistance. The C(V) measurementsmake it possible to monitor sheet carrier density vs. etchdepth. Furthermore, the C(V) measurement gives large-areaaverage values that is not easily obtained with AFMmeasurements.

Ämnesord

TEKNIK OCH TEKNOLOGIER  -- Elektroteknik och elektronik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Electrical Engineering, Electronic Engineering, Information 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)

Nyckelord

AlGaN/GaN

recess etch

ohmic contact

heterostructure

Publikations- och innehållstyp

art (ämneskategori)

ref (ämneskategori)