Select transistor modulated cell array structure test application in EEPROM process reliability

An evaluation of the extrinsic cells number in a memory array using cross-correlation products and deconvolution: an instance of a microelectronics experimental inverse problem

“…In order to determine the number of those singular or extrinsic cells, responsible for the hump, several classical approaches exist. Historically, as in [7,9], it has been shown that the transconductance of an EEPROM CAST can be rebuilt from a cell model transconductance, an assumed Gaussian distribution of V T for intrinsic cells and a singular Dirac distribution for extrinsic ones (assuming that each cell in the CAST has the same transcharacteristic shape as the model one). Moreover, a subtle study of the polarization of the select transistor allows us to extract the standard deviation of the distribution density of the intrinsic cell: the select polarization influencing the transconductance peak of an unitary cell (for details of the structure, see for instance [3,4]).…”

“…In the case of a moderate stress (as illustrated by Figure 2), it is not necessary to extract the intrinsic cell density distribution in order to evaluate the number of extrinsic ones. The latter could be found by different inverse resolutions of Gaussian deconvolution, for instance by extraction of statistical parameters [7,9] or by a Gaussian deconvolution procedure as classically done in a medical device [10,11]. In order to avoid the extraction of the intrinsic part of the curve, we have recently proposed two non-computing methods to estimate the number of extrinsic cells in an EEPROM CAST [12,13].…”

A new method to quantify retention-failed cells of an EEPROM CAST

“…This test structure is a simple tool to qualify and to monitor data retention and oxide integrity [1][2][3][4]. It is used for having information on intrinsic and extrinsic behaviour of cells into a statistically meaningful population.…”

“…Then quantification of those cells is interesting for electrical diagnosis and it is important for improving their process. We can find in the previous literature [1][2][3] a calculative method, based on modelling, to extract the V T distribution of the cells which compose the CAST. In this paper we proposed a new methodology, based only on experimental data, which allows us to localize and to quantify the extrinsic cells which compose the hump of the I D -V CG characteristic.…”

A new technique to characterize endurance of EEPROM tunnel oxides

“…6) and that precisely occurs for the same maximum current density. Actually it is known that such current spikes can lead to an supplemental enhancement of the tunnel oxide degradation [10]. However, a clarification of this topic requires accumulation of more specific data.…”