residual of boron deposited on the dielectric and still remaining on the dielectric 14 the second b 2 h 6 atomic layer caps the in situ heater material 20 next as shown in fig4 a dielectric layer 26 is blanket deposited over the structure and then planarized down to the upper surface 28 of the dielectric 14 as shown in fig5 finally a chalcogenide layer 30 is deposited as indicated in fig6 the vertical heater material 20 makes a small area or point contact with the chalcogenide layer 30 thereafter the chalcogenide layer may be covered with additional layers including another electrode or metal layer not shown then additional layers also not shown may be deposited such as the layers forming an ovonic threshold switch as one example in some embodiments the surface area of contact between the vertically oriented heater material 20 and the chalcogenide layer 30 is governed by the thickness of the deposition of the heater material 20 using atomic layer deposition this layer can be made extremely small resulting in a very small area of contact between the chalcogenide layer 30 and the heater material 20 while the figures depict the formation of the single cell a large number of cells may be formed at the same time for example by forming.