Punchthrough-Diode-Based Bipolar RRAM Selector by Si Epitaxy

We propose an epitaxial punchthrough diode for bipolar resistance RAM (RRAM) selector application. Epitaxial Si:C process is used to deposit
$\hbox{n}^+/\hbox{p}/\hbox{n}^+$
layers which are fabricated into 300-nm-diameter vertical punchthrough diodes. High on-current density of
$> \hbox{1}\ \hbox{MA/cm}^{2}$
and high on/off current ratio of
$>$
250 and
$>$
4700 (at opposite polarities) are observed. A switching speed of
$<$
10 ns is measured. On-voltage designability is demonstrated by tuning the p-region doping and length. The comparison of experimental
$IV$
with Sentaurus TCAD-simulated
$IV$
characteristics confirms the punchthrough mechanism. Comparison with other bipolar RRAM selector technologies highlights the overall advantages of punchthrough-based selector.