Analytical model for predicting current mismatch in metal oxide semiconductor arrays

摘要

A system and method for designing integrated circuits and predicting current mismatch in a metal oxide semiconductor (MOS) array. A first subset of cells in the MOS array is selected and current measured for each of these cells. Standard deviation of current for each cell in the first subset of cells is determined with respect to current of a reference cell. Standard deviation of local variation can be determined using the determined standard deviation of current for one or more cells in the first subset. Standard deviations of variation induced by, for example, poly density gradient effects, in the x and/or y direction of the array can then be determined and current mismatch for any cell in the array determined therefrom.

主权项

1. A method of characterizing a metal oxide semiconductor (MOS) array comprising the steps of:
modeling a metal oxide semiconductor (MOS) array having a plurality of rows and columns defining a set of cells; forming a first subset of cells of the set on a substrate; measuring current for each cell in the first subset of cells; determining standard deviation of current for each cell in the first subset of cells with respect to current of a reference cell in the array; determining standard deviation of local variation as a function of the determined standard deviation of current for one or more cells in the first subset; determining standard deviation of variation induced due to a poly density gradient effect in a first direction as a function of the determined standard deviation of local variation and the determined standard deviation of current for one or more cells in the first subset; and determining standard deviation of variation induced due to a poly density gradient effect in a second direction as a function of the determined standard deviation of local variation and the determined standard deviation of current for one or more cells in the first subset; and performing computations in a processor to characterize a second subset of cells of the set as a function of the determined standard deviation of variation induced due to a poly density gradient effect in the first direction and/or second direction, the second subset comprising one or more cells each mutually exclusive of the first subset of cells.