Preparation and properties of a junction between p-SiC and n-CdSe

2015

Current leakage and hysteresis characteristics of a MOS capacitor containing nanocrystalline CdSe embedded ZrHfO high-k gate dielectric at different temperatures have been investigated. Variation of the temperature changes the supply and energy state of charges from the Si wafer, the charge trapping and retaining properties of the embedded nanocrystal, and the conductivity of the high-k stack. They are responsible for the magnitude and hysteresis of the leakage current. Depending on the polarity and magnitude of the applied voltage and the substrate temperature, charges are transferred following the Schottky emission, Poole-Frenkel, or Fowler-Nordheim mechanism. The leakage current hysteresis of the nanocrystalline CdSe embedded sample is smaller than that of the control sample, and the difference increases as the temperature rises. These phenomena are related to the defect density, the physical thickness, and the charge trapping mechanism.

Section: Introductionmentioning

confidence: 99%

(Invited) Temperature Influence on Current Leakage and Hysteresis of Nc-CdSe Embedded Zr-Doped HfO₂ High-k Dielectric Nonvolatile Memory

Zhang

2015

“…Cadmium selenide (CdSe) is a n-type semiconductor with a large work function of 4.8-5.0 eV. It can be made into nanocrystals to embed in the high-k film to trap charges [13]. The nanocrystalline CdSe (nc-CdSe) embedded ZrHfO metal-oxide-semiconductor (MOS) memory has a large charge trapping density with a long retention time [14].…”

Section: Introductionmentioning

confidence: 99%

Temperature Effect on Memory Functions of the nc-CdSe Embedded ZrHfO High-k MOS Device

Zhang

2014

The temperature effect on the memory characteristics of the MOS capacitor containing the nanocrystalline CdSe embedded ZrHfO high-k gate dielectric has been investigated. At the high temperature, the Coulomb blockade phenomenon is suppressed and the leakage current is increased due to the relative high conductivity of the dielectric film. At the same time, the density of interface states is high and the memory window is small. When the temperature is increased, the hole trapping capacity is enhanced because of the improve the supply of holes from the Si. However, the electron trapping capacity is reduced because of the easy transfer of electrons through the high-k stack. The frequency dispersion phenomenon is enhanced at the high temperature. The temperature has strong influence on the carrier generation, transport, and trapping at the interface and the bulk film.

“…were better than those of the HfO 2 [3]. CdSe, which is a n-type semiconductor with a large work function, i.e., 4.8 eV to 5 eV, can be embedded in the ZrHfO film as a charge trapping medium [4]. The CdSe embedded ZrHfO film can trap a large number of electrons or holes for a long period depending on the polarity and magnitude of the applied gate voltage (V g ) [5].…”

Section: Introductionmentioning

confidence: 99%

CdSe Embedded ZrHfO Gate Dielectric Nonvolatile Memories – Charge Trapping and Breakdown Studies

Lin

2013

MOS capacitors composed of nc-CdSe embedded ZrHfO high-k gate dielectric stacks were fabricated and investigated on the charge trapping and breakdown mechanisms. The interface layer between the high-k film and Si wafer was transformed to a more SiO2-like HfSixOy group after the inclusion of nc-CdSe layer. The frequency-dependent conductance-voltage measurement result shows that part of the trapped charges were loosely trapped at the nc-CdSe/ZrHfO interface and easily tunneled back to the Si substrate under low frequency measurement condition. Compared with the control sample, the nc-CdSe embedded sample has a larger leakage current and a higher breakdown voltage due to the formation of new leakage paths and a larger physical thickness. The trapped charges can be retained in the nc-CdSe site after the breakdown of the high-k film.