Conductance technique measurements of the density of interface states between ZnS:Mn and p-silicon

Abstract

Capacitance and conductance measurements are presented for dc-driven Au/ZnS:Mn/p-Si electroluminescence metal-insulator-semiconductor (MIS) devices, where the ZnS:Mn films are deposited by radio frequency sputtering. Stable dc operation is achieved by introducing oxygen into the film during deposition and subsequently annealing. The effect of the post-deposition annealing upon the density of states at the ZnS:Mn/p-Si interface is investigated. As deposited, the devices show unusual MIS C-V characteristics, that indicate a very high interface state density. Annealing at 700 °C, normal C-V characteristics are observed, indicating that the very high density of states is greatly reduced. For these films the conductance technique has been used to measure the density of states at the interface between the ZnS:Mn and p-Si. The statistical model is found to describe most accurately the interface state conductance response. The interface state density consists of a tail of states that varies between 3.7×1013 cm−2 eV−1 at the silicon Fermi level and 1.1×1013 cm−2 eV−1 at the silicon mid-gap. A small peak is superimposed upon this tail at (−0.16±0.01) eV below mid-gap. The tail of states is believed to be intrinsic to the ZnS:Mn/p-Si interface, but evidence suggests that the small peak is due to the presence of oxygen, which is shown by secondary-ion mass spectrometry analysis to accumulate at the interface after annealing at 700 °C. It seems likely that the very high density of interface states in as deposited devices is a consequence of a plasma damage to the silicon surface during growth, creating defects such as silicon dangling bonds. One possible explanation for the decrease in this density is that by annealing at 700 °C, oxygen in the bulk of the film diffuses to the interface, where it mops up these defects by forming compounds such as SiOx. A simpler model of interface recrystallization is also suggested. The doping density in the depletion region of the silicon is calculated as (7.5±0.5)×1014 cm−3, and the interface state capture cross section for holes is found to have mean value of approximately 10−15 cm−2.

MBE-grown Si and Si1−xGexquantum dots embedded within epitaxial Gd2O3on Si(111) substrate for floating gate memory device

“…The capacitance value is found to be the same for all frequencies in inversion. Figure 7(b) clearly exhibits the variation in hysteresis width with frequency, though it is less in comparison with the previously reported interface trap's related response [21,22]. The (G/ω)-V characteristics of the Si 1−x Ge x QD1L device is shown in figure 7(c), and the FWHM and peak voltage of the conductance are plotted in figure 7(d).…”

“…There might be a small contribution from interface traps, which can be observed from the fact that the FWHM of the conductance peak for the discharging condition varies slightly near 100 kHz. It can also be noted that the conductance peak intensity or peak position of the device exhibits a very small variation with frequency, though much less compared to the typical response from the interface traps [21,22].…”

Characterization and modeling of fast traps in thermal agglomerating germanium nanocrystal metal-oxide-semiconductor capacitor

“…III B and considered to be sensitive to investigate these traps. [17][18][19] Especially, the little larger window for sample B than for sample A indicates that the PMA treatment has only a limited effect to avoid charge leakage in NCs; we will discuss the reason in Sec. III E.…”

“…13,15 Besides for the fast traps in the oxide around the NCs, conductance-voltage ͑G-V͒ measurement is considered to be sensitive and provides the dynamic information related to the trap density. [17][18][19] as tunneling layer have also been estimated and studied by using the frequency-dependent G-V results. 21 In our work, the Ge NCs are synthesized by using the rapid-thermal annealing ͑RTA͒ and embedded into a threelayer ͑SiO 2 / NCs-Ge/ SiO 2 ͒ structure.…”

Electrical and structural characteristics of yttrium oxide films deposited by rf-magnetron sputtering on n-Si

“…To the best of our knowledge only a few works have been reported in the past 14,[31][32][33][34] showing a parallel shift of measured C -V's with frequency. An interesting common feature in these works is that all of them report on interfaces between silicon and poor dielectric materials ͓e.g., ZnS:Mn ͑Ref.…”