Electrical properties of amorphous aluminum oxide thin films

Silicon oxide (SiO2) gate length, gate thickness, junction depth, and source/drain extension scaling have allowed metal-oxide-semiconductor (MOS) gate dimensions to approach the current =<100 nm range. High dielectric constant materials for gate insulation and low resistivity junctions must be developed in order to enable further scaling of these devices. Aluminum oxide (Al2O3), with a bandgap of 9.9 eV, is an especially promising material for use as a gate insulator; however, conventional Al2O3 processing techniques suffer from excessive thermal requirements. We have grown (alpha)-Al2O3 thin films directly on silicon (1 0 0) at room temperature using pulsed laser deposition (PLD). Atomic-resolution transmission electron microscopy, Z-contrast scanning transmission electron microscopy, capacitance-voltage measurements, and current-voltage measurements were used to determine the nanoscale features and electrical properties of amorphous Al2O3 thin films. Our results suggest that amorphous Al2O3 films prepared using pulsed laser deposition may serve as high dielectric constant materials for next generation electronic devices.