Nanoscale electrical characterization of Si-nc based memory metal-oxide-semiconductor devices

Abstract

Conduction mechanisms and charge storage in Si-nanocrystals metal-oxide-semiconductor memory devices studied with conducting atomic force microscopy J. Appl. Phys. 98, 056101 (2005); 10.1063/1.2010626The effect of additional oxidation on the memory characteristics of metal-oxide-semiconductor capacitors with Si nanocrystals Appl. Phys. Lett. 82, 4818 (2003); 10.1063/1.1587273 Nanocrystal metal-oxide-semiconductor memories obtained by chemical vapor deposition of Si nanocrystals Memory effects related to deep levels in metal-oxide-semiconductor structure with nanocrystalline SiIn this work, standard and nanoscale experiments have been combined to investigate the electrical properties of metal-oxide-semiconductor ͑MOS͒ memory devices with silicon nanocrystals ͑Si-nc͒ embedded in the gate oxide. The nanometer scale analysis has been performed with a conductive atomic force microscope ͑C-AFM͒ which, thanks to its high lateral resolution, allows the study of areas of only few hundreds of nm 2 . Therefore, with this technique, a very reduced number of Si-nc can be investigated. We have studied the conduction mechanisms, the retention time, and the amount of charge stored in the Si-nc of these structures. The results have demonstrated that Si-nc enhance the gate oxide electrical conduction due to trap assisted tunneling. On the other hand, Si-nc can act as trapping sites. The amount of charge stored in Si-nc has been estimated through the change induced in the barrier height measured from the current-voltage ͑I-V͒ curves ͑at the nanoscale, with C-AFM͒ and from the flat band voltage shift determined from the capacitance-voltage ͑C-V͒ characteristics measured on polygated structures. Both procedures have shown an occupation level of ϳ20% of the Si-nc. The retention times, estimated at the nanoscale and from standard electrical characterization, are consistent. Moreover, contrary to standard characterization techniques, C-AFM allows the mesurement of lateral leakage currents in memories based on high density trapping sites. All these results allow one to conclude that C-AFM is a very suitable tool in performing a detailed investigation of the performance of memory devices based on MOS structures with Si-nc at the nanoscale.

Graphene‐Coated Atomic Force Microscope Tips for Reliable Nanoscale Electrical Characterization

“…For as‐received samples (Figure 2c) the DB site correlates to a huge hillock up to 31.2 nm tall. This well‐known behavior, which is related to the violence of the uncontrolled DB event in the insulating samples,20 has been previously observed by other research groups, and it has been mainly related to two phenomena. The first is the so‐called Dielectric Breakdown Induced Epitaxy (DBIE),21 which is related to the microstructural damages triggered by DB‐induced thermo‐chemical reactions in the oxide.…”

Inherent paramagnetic defects in layered Si/SiO2 superstructures with Si nanocrystals

“…Many top characterization techniques have been applied, such as the morphological tools ͓transmission electron microscopy ͑TEM͒, 7,37,38 atomic force microscopy, 5,39 and electrostatic force microscopy 39 ͔, in combination with small angle x-ray scattering 40 and optical measurements, mainly PL. Theory, experiment, and technology collaborate with the intent of understanding the optical processes that take place and make more efficient and industry friendly optically active Si-based materials.…”

Efficiency and reliability enhancement of silicon nanocrystal field-effect luminescence from nitride-oxide gate stacks

“…[1][2][3][4][5][6] In the last years, an increasing number of articles dealing with electroluminescence ͑EL͒ from Si-nc embedded in silicon oxide ͑Si-nc/ SiO 2 ͒ devices has been published. Many of them report emission under direct current ͑dc͒ polarization, [7][8][9] which usually leads to low emission efficiency and fast degradation.…”