Impact of Single Charge Trapping in Nano-MOSFETs—Electrostatics Versus Transport Effects

Many-particle transport in the channel of quantum wire double-gate field-effect transistors with charged atomistic impurities

“…1 In addition, this number and the position of dopant atoms, introduced either deliberately to improve device characteristics or accidentally from contamination sources, will vary among electron devices. In particular, many simulations have been done using drift-diffusion approaches, 2, [11][12][13][14][15][16][17][18][19][20][21][22][23][24][25] Monte Carlo ͑MC͒ solution of the Boltzmann equation, [3][4][5][6][25][26][27][28] and quantum approaches. [11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28] This particular phenomenon, known as discrete dopant induced fluctuation ͑DDIF͒, represents a little fraction of the whole set of nondesirable effects arising from the atomistic nature of matter, but is considered as one of the main drawbacks in downscaling complementary metal-oxide semiconductor ͑CMOS͒ technology.…”

“…In order to predict the impact of such phenomena in future deca-nano transistors, during the last decade, several works, both experimental and theoretical, have been carried out. 4,25,26 On the other hand, the "atomistic" resolution of individual charges in drift-diffusion simulations using fine meshes generate some problems. [7][8][9][10]25 The aim of the drift-diffusion simulations of DDIF, instead of predicting the characteristics of a single device, is focused on obtaining quantitative estimations of the variance of basic design parameters, such as threshold voltage, subthreshold slope, or drive current for a whole ensemble of microscopically different devices.…”

Reliability of NAND Flash Memories: Planar Cells and Emerging Issues in 3D Devices

“…Simulations were conducted within the drift-diffusion framework, neglecting the field dependence of mobility to avoid unphysical effects close to the ionized dopants and RTN trap. The impact of Coulomb scattering on the RTN and variability characteristic of such MOSFETs has been studied in [114][115][116][117], showing that those effects are barely relevant for NAND Flash, that are read in the subthreshold regime. Charge quantization was instead accounted for via the density-gradient correction to the drift-diffusion formalism [118,119].…”

Many-particle Monte Carlo Approach to Electron Transport

“…The problem comes then from the analytical nature of the short-range corrections, which can lead to unphysically large forces that cause artificial heating and cooling (for acceptors and donors respectively) of the carriers (Gross et al, 2000b;Ramey & Ferry, 2003). Again, this problem can be amended by introducing modifications of the analytical expressions of the Coulomb interaction in the short-range region (Alexander et al, 2005; or by implementing density gradient (quantum) corrections that accounts for the formation of bound states in the donor induced wells (Asenov et al, 2009;Vasileska & Ahmed, 2005). Unfortunately, even all the above improvements of the MC solution of the BTE can fail when device dimensions are aggressively reduced to a very few nanometers either in lateral or longitudinal directions.…”