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Defects and traps in strained-Si n-type metal-oxide-semiconductor field effect transistors (MOSFETs) are studied in detail. The inelastic electron tunneling spectroscopy (IETS) technique is shown to be capable of probing traps in ultrathin gate dielectrics and obtain the energies and spatial locations of the traps. Detailed analyses of electrical stress-induced build-up of traps and electrically active bonding defects and identification of the trap-features including trap-assisted conduction and charge-trapping have been performed. The location and energies of the traps are estimated from the IETS spectra measured at both bias polarities. Identification of the acoustic and optical phonon modes (inelastic) as well as trap-features (elastic) helps in better understandings of the complex transport-mechanisms in gate dielectrics on strained layers. [ABSTRACT FROM AUTHOR]

The interfacial and electrical properties of RF sputtered La2O3 on p-GaAs substrates with and without ultrathin Si interface passivation layer (IPL) are reported. X-ray photoelectron spectroscopy (XPS) studies revealed the formation of thermally stable interfacial native oxide (Ga-oxide and As-oxide) for La2O3/Si/p-GaAs gate stacks. The presence of (La2O3)1-x(SiO2)x at the interface prevented the formation of La-hydroxide which improved the metal-oxide-semiconductor (MOS) device characteristics, such as interface state density (∼1.2×1012eV-1cm-2), frequency dispersion (∼7%), and hysteresis voltage (∼260 mV). A gate leakage current density of 1.1×10-5 A.cm-2 has been achieved at Vfb-1 V for an equivalent oxide thickness of 3.4 nm and small flat-band voltage instability under constant voltage stressing was observed. The electrical properties of Al/La2O3/Si/p-GaAs MOS capacitors were found to improve after post deposition annealing at 500°C. [ABSTRACT FROM AUTHOR]

Microwave plasma oxidation (below 200 °C) of partially strain-compensated Si[sub 1-x-y]Ge[sub x]C[sub y] (Ge:C=20:1 and 40:1) with and without a Si cap layer is reported. The electrical properties of grown oxides have been characterized using a metal–oxide–semiconductor structure. Fixed oxide charge density and mid-gap interface trap density are found to be 2.9×10[sup 11]/cm[sup 2] and 8.8×10[sup 11]/cm[sup 2]/eV, respectively, for directly oxidized Si[sub 0.79]Ge[sub 0.2]C[sub 0.01] film. The oxide on samples with low C (0.5%) concentration, exhibits hole trapping, whereas electron trapping is observed for oxides on alloys containing 1% C. © 1998 American Institute of Physics. [ABSTRACT FROM AUTHOR]