Acoustic Deep-Level Transient Spectroscopy of MIS Structures

Abstract

A new method of determining and characterization of traps at the insulator‐semiconductor interface is presented. This method, acoustic deep‐level transient spectroscopy (A‐DLTS), is based on the acoustoelectric response effect observed at the interface. A theoretical analysis of the acoustoelectric transient measurements in accordance to capacitance ones is also presented. The temperature dependence of the acoustoelectric response after bias voltage step application is investigated and the activation energies are calculated. Some other parameters of interface traps are also determined. The method is verified by the investigation of both, n‐ and p‐type SiO2Si interface states.

Acoustic spectroscopy and electrical characterization of SiO2/Si structures with ultrathin SiO2 layers formed by nitric acid oxidation

“…Current-voltage (I − V ) characteristics were measured using an HP 4140B picoampermeter and capacitance-voltage (C − V ) curves were recorded with an HP 4192A impedance analyzer. The A-DLTS technique we used is based on the fact that the time development of the amplitude of the measured ARS, produced by SiO 2 /Si interfaces when a hf longitudinal acoustic wave passes through the MOS structure, is proportional to the nonequilibrium carrier density [7]. After an injection bias pulse has been applied to the structure, the decay time constant associated with the relaxation of the ARS amplitude is a direct measure of the time constant associated with the relaxation processes of injected carriers.…”

Acoustic Spectroscopy of Nanostructures in Condensed Matter

“…The surface acoustic wave (SAW) technique uses a nonlinear AE interaction between the SAW electric field and free carriers in an interface region which generates a transverse AE signal (TAS) across the structure [4]. The longitudinal acoustic wave (LAW) technique uses an acoustoelectric response signal observed at the interface of the semiconductor structure when a longitudinal acoustic wave propagates through the structure [5,6].…”

“…The ARS produced by a MOS structure propagating by longitudinal acoustic wave can be then expressed using the similarity with the case of electromechanical capacitance transducer of thin planar structure (d<<λ) by the relation [5,7] ( ) ( )…”

Analysis of A-DLTS spectra of MOS structures with thin NAOS SiO2 layers

“…The acoustic wave followed by the pressure modulation of charge density evokes the change of the potential difference that manifests as an ARS signal [16]. The ARS produced by a MOS structure propagating by longitudinal acoustic wave can be then expressed using the similarity with the case of electromechanical capacitance transducer of thin planar structure ( λ) [11,12,16,17] by the re-…”

“…One of them, the longitudinal acoustic wave (LAW) technique, uses an acoustoelectric response signal (ARS) observed at the interface of the semiconductor structure when a longitudinal acoustic wave propagates through the structure [16,17]. ARS is extremely sensitive to any changes in the space charge distribution in the interface region so dependence on the external voltage (U − V G characteristic) and time development after an injection pulse has been applied to the structure (A-DLTS) can be used to study the interface states properties including their activation energy, capture cross-section, concentration and interface states distribution.…”