  This paper proposes a diagnosis scheme aimed at reducing diagnosis time of
distributed small embedded SRAMs (e-SRAMs). This scheme improves the one
proposed in [A parallel built-in self-diagnostic method for embedded memory
buffers, A parallel built-in self-diagnostic method for embedded memory
arrays]. The improvements are mainly two-fold. On one hand, the diagnosis of
time-consuming Data Retention Faults (DRFs), which is neglected by the
diagnosis architecture in [A parallel built-in self-diagnostic method for
embedded memory buffers, A parallel built-in self-diagnostic method for
embedded memory arrays], is now considered and performed via a DFT technique
referred to as the "No Write Recovery Test Mode (NWRTM)". On the other hand, a
pair comprising a Serial to Parallel Converter (SPC) and a Parallel to Serial
Converter (PSC) is utilized to replace the bi-directional serial interface, to
avoid the problems of serial fault masking and defect rate dependent diagnosis.
Results from our evaluations show that the proposed diagnosis scheme achieves
an increased diagnosis coverage and reduces diagnosis time compared to those
obtained in [A parallel built-in self-diagnostic method for embedded memory
buffers, A parallel built-in self-diagnostic method for embedded memory
arrays], with neglectable extra area cost.
