Electrochemical Charging of Thermal SiO2 Films by Injected Electron Currents

Abstract

When electron currents flow in thermal SiO2 films which have been exposed to water, a buildup of negative charge occurs in the oxide. This paper describes a series of experiments designed to characterize this charging effect. It is found that if water is diffused into a SiO2 film, water related centers are formed which act like electron traps with capture cross section of approximately 1.5 × 10−17 cm2. Experiments are described which show that when one of these centers captures an electron, atomic hydrogen is released which diffuses away and escapes or reacts and a stable negative charge is left behind. Electrochemical charging effects of this type have not previously been considered, although they may play a very important role in some semiconductor device failure effects.

Growth and surface potential characterization of Bi2Te3 nanoplates

“…Multiple-reflection attenuated-total-reflection FTIR spectrometry (ATR-FTIR) have found evidence for electrochemical trapping of electrons by SiOH silanol groups on the SiO 2 substrate. 30,31 SiOH concentration on the SiO 2 surface has been determined to be ∼(3-7) × 10 13 cm -2 in a number of studies. 32,33 This concentration is nevertheless electronically significant, as it exceeds or is comparative to the typical carrier concentration of 10 13 cm -2 found recently in single Bi 2 Te 3 NP devices with a top gate and Bi 2 Te 3 nanoribbon based field-effect transistor (FET).…”

Nature of intrinsic and extrinsic electron trapping in SiO2

“…So far, the dominant electron traps have been associated with impurity-related centers, in particular, the hydrogen-related network fragments. [10][11][12][13] It has been well established that electrons can be trapped by Ge impurities substituting for Si in both α-quartz 14 and in a-SiO 2 15 with models of these centers recently revisited by Griscom. 16 A defect consisting of an extra electron trapped at a four-coordinated silicon atom and stabilized by an adjacent interstitial Li ion has been observed in quartz.…”

Hydrogen-atom-mediated electrochemistry

“…The SiO 2 thin film, which is thermally grown on highly n-doped Si (the fabrication method and properties are described in detail in Methods and the Supplementary Information), has a highly dielectric structure with minimal defects. Therefore, it permits both the selective migration of protons and the diffusion of electrogenerated H atoms 9 in the middle of the electrical potential gradient. This result suggests that H atoms in the EOS system could be used as electron mediators on dielectric oxide layers acting as 'chemical electrodes' for electrochemical reactions.…”

“…In this work, we introduced thermally grown silicon dioxide (SiO 2 ), a dense and stable dielectric layer, and explored the novel phenomena that could be observed in this electrochemical system. Thermal SiO 2 is a dielectric material used for conventional metal/insulator/metal capacitors 6 , and SiO 2 films are widely used as gate insulators of metal/oxide/semiconductor (MOS) devices 7 , in which the field-induced drift of protons to the Si/SiO 2 interface and their interactions with electrons can create hydrogen (H) atoms at the interface 8,9 . Shkrob et al 10 demonstrated that protons were reduced to generate mobile H atoms in B 2 O 3 glasses at room temperature.…”