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 an array in an IC, comprising the steps of:
forming an array of cells having a set of cells on a substrate; measuring current for each cell in a first subset of the set of cells; determining a variance of current for each cell in the first subset of cells with respect to current of a reference cell in the array; determining local variance of current for one or more cells in the first subset of cells; using a processor to calculate variance of current due to a poly density gradient effect in a first direction based on the determined local variance of current and the determined variance of current with respect to the reference cell in the first subset of cells; and using the processor to calculate a current mismatch of another cell of the array from the determined local variance and the calculated variance of current due to the poly density gradient effect in the first direction, said another cell being excluded from the first subset of cells.