Title :
Surface leakage currents in SiNx passivated AlGaN/GaN HFETs
Author :
Tan, W.S. ; Uren, M.J. ; Houston, P.A. ; Green, R.T. ; Balmer, R.S. ; Martin, T.
Author_Institution :
Dept. of Electron. & Electr. Eng., Univ. of Sheffield, UK
Abstract :
A novel guarded surface leakage test structure is used to isolate the surface and bulk leakage contributions to gate current in AlGaN/GaN HFETs. Passivation with various recipes of SiNx always resulted in the commonly observed increase in gate leakage, which was found to be dominated by bulk leakage through the AlGaN. However, high temperature deposited SiNx recipes gave a 1-2 orders reduction in surface leakage, whereas low temperature deposition gave an increase. Gate lag measurements were found to correlate closely with the surface leakage component, giving direct evidence that the key device problem of current slump is associated with current flow at the AlGaN surface.
Keywords :
III-V semiconductors; aluminium compounds; field effect transistors; gallium compounds; isolation technology; leakage currents; passivation; silicon compounds; wide band gap semiconductors; AlGaN-GaN; SiN; bulk leakage; current slump; gate lag; gate leakage; heterostructure field effect transistors; low temperature deposition; passivation; surface leakage currents; surface leakage test structure; Aluminum gallium nitride; Gallium nitride; Gate leakage; HEMTs; Leakage current; MODFETs; Passivation; Silicon compounds; Temperature; Testing; Gallium nitride; SiN; current slump; gate lag; heterostructure field-effect transistors (HFETs); leakage currents;
Journal_Title :
Electron Device Letters, IEEE
DOI :
10.1109/LED.2005.860383
