of fig1 and the first embodiment of fig2 the initial etching of the bottom electrode continues all the way into the substrates 27 and 41 respectively of the capacitors this results in the fences 35 43 formed from the respective teos and hcd nitride materials in the second embodiment the rie processing of the bottom electrode can etch into the underlying oxygen barrier layers 31 or ti glue layer 25 but the etch is stopped before the etch frontier reaches the teos layer 27 as illustrated in fig4 and step 103 of fig8 the metal fences 33 are formed during the bottom electrode etching next as shown in fig5 and step 105 of fig8 an oxygen stopping cover layer 45 is deposited over the outer portions including the teos hardmask 23 metal fences 33 and remaining underlying layers such as the barrier layers 31 and ti glue layer 25 the oxygen stopping cover layer 45 can be composed of a nitride such as hcd nitride or al 2 o 3 for example the cover layer 45 can be deposited using pvd physical vapor deposition cvd chemical vapor deposition or ald atomic layer deposition processes for example as illustrated by step 107 of fig8 and by fig6 an additional rie processing step or continuation of the previous rie processing step is performed in which the etch is continued into the teos substrate 27 the rie process is anisotropic etching away more horizontally oriented portions of the oxygen stopping cover layer 45 while leaving more vertically oriented portions of the oxygen.