Electrical conduction and dielectric breakdown in aluminum oxide insulators on silicon

Abstract

Leakage currents and dielectric breakdown were studied in MIS capacitors of metal-aluminum oxide-silicon. The aluminum oxide was produced by thermally oxidizing AlN at 800-1100 C under dry O 2 conditions. The AlN films were deposited by RF magnetron sputtering on p-type Si (100) substrates. Thermal oxidation produced Al 2 O 3 with a thickness and structure that depended on the process time and temperature. The MIS capacitors exhibited the charge regimes of accumulation, depletion, and inversion on the Si semiconductor surface. The best electrical properties were obtained when all of the AlN was fully oxidized to Al 2 O 3 with no residual AlN. The MIS flatband voltage was near 0 V, the net oxide trapped charge density, ox , was less than 10 11 cm 2 , and the interface trap density, , was less than 10 11 cm 2 eV 1 . At an oxide electric field of 0.3 MV/cm, the leakage current density was less than 10 7 A cm 2 , with a resistivity greater than 10 12 -cm. The critical field for dielectric breakdown ranged from 4 to 5 MV/cm. The temperature dependence of the current versus electric field indicated that the conduction mechanism was Frenkel-Poole emission, which has the interesting property that higher temperatures reduce the current. This may be important for the reliability of circuits operating under extreme conditions. The dielectric constant ranged from 3 to 9. The excellent electronic quality of aluminum oxide may be attractive for field effect transistor applications.

Low Voltage Electrowetting-on-Dielectric for Microfluidic Systems

“…It is noted that both the scatter in VB, EB and the difference between VB+(EB+) and VB-(EB-) decrease with increasing thickness (i.e. increasing anodization voltage).The breakdown field for the oxides ranges between 3-7 MV/cm with the value leveling to 7 MV/cm in both polarities with increasing film thickness (Figure 18(b)), similar to the values observed in other anodic aluminum oxide films [56], but higher than thermally oxidized aluminum (5MV/cm) [88], suggesting a better quality film.…”

Identification of current transport mechanism in Al2O3 thin films for memory applications

“…It has been suggested in literature (Kolodzey et al 2000) that sputterred Al 2 O 3 has an increased capacitive coupling and performance compared to conventional SiO 2 . Al 2 O 3 is found to be immune to erase saturation and its memory retention capability is superior to that of HfO 2 (Wellekens et al 2007).…”

“…It is chemically and thermodynamically stable and forms an atomically abrupt interface with Si (Afanas 'Ev et al 2002), making it a suitable replacement for SiO 2 . Al 2 O 3 has a large band gap (&8.7 eV) (Robertson 2006;Kolodzey et al 2000) and higher crystallization temperature compared to HfO 2 (Robertson 2006;Bouazra et al 2008) and proven electrical characteristics. Hence, it is rightly being pursued for use as blocking dielectric in flash memories (Dutta et al 2011).…”

Kinetic Monte Carlo of transport processes in Al/AlOx/Au-layers: Impact of defects

“…9 In these applications AlO x films are mostly produced by ALD, 7,10 RIE-plasma-growth 6 or thermal oxidation. 1 Al/Al 2 O 3 /Al tunneling contacts were addressed analytically already in 1963 11 while refined models for ultrathin AlO x have been derived later on. 12 Recently, the types of defects in AlO x , have been investigated, as they influence conduction pathways, like trap-assisted-tunneling (TAT) and Poole-Frenkel (PF) emission.…”

“…1,2 In fact, aluminum oxide, AlO x , turned out to be useful for many electronic applications like silicon-onsapphire for CMOS technology, 3 organic devices, 4 THz-nano-rectennas, 5 nTP tunnel diodes, 6 gate metals on III/V-semiconductors 7,8 and for resistive switches. 9 In these applications AlO x films are mostly produced by ALD, 7,10 RIE-plasma-growth 6 or thermal oxidation.…”