A source line bias error caused by a voltage drop in a source line of a
non-volatile memory device during a read or verify operation is
addressed. In one approach, a body bias is applied to a substrate of the
non-volatile memory device by coupling the substrate to a source voltage
or a voltage which is a function of the source voltage. In another
approach, a control gate voltage and/or drain voltage, e.g., bit line
voltage, are compensated by referencing them to a voltage which is based
on the source voltage instead of to ground. Various combinations of these
approaches can be used as well. During other operations, such as
programming, erase-verify and sensing of negative threshold voltages, the
source line bias error is not present, so there is no need for a bias or
compensation. A forward body bias can also be compensated.