Title :
Enhancement and Depletion Mode AlGaN/GaN CAVET With Mg-Ion-Implanted GaN as Current Blocking Layer
Author :
Chowdhury, Srabanti ; Swenson, Brian L. ; Mishra, Umesh K.
Author_Institution :
Dept. of Electr. & Comput. Eng., Univ. of California at Santa Barbara, Santa Barbara, CA
fDate :
6/1/2008 12:00:00 AM
Abstract :
Current aperture vertical electron transistor (CAVET) was successfully demonstrated by using Mg-implanted GaN as a current blocking layer for nonalloyed source contacts. A maximum source-drain current of (corresponding to 0.22 A/mm of source) and an extrinsic transconductance of 54 mS/mm of source were achieved. Threshold voltage as high as 0.6 V was realized by plasma exposure for 10 min, increasing the transconductance of the device to 140 mS/mm of source. Thus, a normally off CAVET was demonstrated for the first time. The increase in by plasma exposure for a given bias was due to etching of the AlGaN barrier. The shift of threshold voltage and the varied directly with the time of exposure. There was no significant dispersion in these devices.
Keywords :
III-V semiconductors; aluminium compounds; etching; field effect transistors; gallium compounds; magnesium; wide band gap semiconductors; AlGaN-GaN; CAVET; GaN:Mg; barrier etching; current aperture vertical electron transistor; current blocking layer; device transconductance; maximum source-drain current; nonalloyed source contacts; plasma exposure; time 10 min; Aluminum gallium nitride; Apertures; Electrons; Etching; Gallium nitride; Plasma applications; Plasma devices; Plasma sources; Threshold voltage; Transconductance; $hbox{CF}_{4}$ plasma treatment; AlGaN/GaN; Mg implanted; current aperture vertical electron transistor (CAVET); normally off; threshold voltage;
Journal_Title :
Electron Device Letters, IEEE
DOI :
10.1109/LED.2008.922982
