Title :
The effect of gate material on dielectric characteristics and conduction mechanism of Ta2O5 MOS structures
Author :
Pecovska-Gjorgjevich, M. ; Novkovski, N. ; Atanassova, E. ; Spasov, D.
Author_Institution :
Inst. of Phys., St. Cyril & Methodius Univ., Skopje, Macedonia
Abstract :
Ta2O5 MOS structures with different gate materials (Al, Au, W, TiN, TiN/W) were studied in order to investigate the effect of gate material on the leakage currents, capacity and conduction mechanism. The leakage current density is found for all samples bellow 10-7 A/cm2 till 0.64 -1 MV/cm, except for TiN/W gate electrode capacitors which show higher currents. Results from accumulation regime confirm Schottky emission for low fields (bellow 0.8 MV/cm) and change to Pool-Frankel mechanism for medium fields. The capacitors were subjected to constant current stress with low currents injected and time-dependent voltage change was investigated. Breakdown fields for all films are under 2 MV/cm, except for Au structures with EBD>2 MV/cm.
Keywords :
MOS capacitors; Poole-Frenkel effect; Schottky effect; aluminium; current density; dielectric thin films; electric breakdown; electrical conductivity; gold; leakage currents; stress effects; tantalum compounds; titanium compounds; tungsten; Au structures; Pool-Frankel mechanism; Schottky emission; Ta2O5 MOS structures; Ta2O5-Al; Ta2O5-Au; Ta2O5-TiN; Ta2O5-TiN-W; Ta2O5-W; breakdown fields; conduction mechanism; constant current stress; current injection; dielectric properties; gate electrode capacitors; gate material effect; leakage current density; thin films; Bellows; Capacitors; Conducting materials; Dielectric materials; Electrodes; Gold; Leakage current; Stress; Tin; Voltage;
Conference_Titel :
Solid Dielectrics, 2004. ICSD 2004. Proceedings of the 2004 IEEE International Conference on
Print_ISBN :
0-7803-8348-6
DOI :
10.1109/ICSD.2004.1350570
