Space-charge-limited current involving carrier injection into impurity bands of high-k insulators

Abstract

Photoelectrical measurements have shown that the current flow through La2Hf2O7 and LaAlO3 high-k insulator layers deposited on silicon takes place via impurity channels. A space charge limited current is evidenced, for different insulator thicknesses and temperatures, by the square law dependence of current versus voltage. The analysis demonstrates that this space charge limited (SCL) current in thin insulator films can be explained only by the presence of impurity channels situated near the Fermi level of the injecting contact. Many other aspects related to the SCL current behavior were found.

Conduction mechanism of leakage current due to the traps in ZrO2thin film

“…where ε i (ε r ε 0 ) is the permittivity of the oxide and μ is the mobility, d is the thickness of oxide, θ is the ratio of free to shallow trapped charge. Goldenblum et al [25] reported that a SCL current can be evidenced if the μθ factor is very small as a result of the high trap level occupancy and the low carrier mobility. By fitting the experimental current densities (J) with equation ( 5), we found the μθ product values ranging from 10 −11 to 10 −9 cm 2 V s −1 , i.e.…”

Investigation of metal-oxide semiconductor field-effect transistor-like Si/SiO2/(nano)crystalline PbS heterostructures

“…Together with the results from photocurrent measurements which show a clear photosignal generated in Si, this proves that part of the source-drain current flows through a conduction channel in Si, after it has been injected transversally in the heterostructure through the SiO 2 insulator. It was shown in [18] that carrier injection through thin film insulators via impurity bands is a possible mechanism for carrier leakage in MOS structures. The inset in Fig.…”