doped semiconductor substrate without p n junctions is to be isolated from the electrical devices then an insulating layer is deposited followed by the deposition of an anode conductive layer if an electrically isolatable vmd device is to be formed on conductive substrate 11 as shown in fig1 b then on the conductive substrate 11 an insulative film or layer 12 is deposited a layer or film of a conductive anode 13 which could be doped polysilicon is then deposited on the insulator layer 12 the material for the conductive substrate 11 could be a silicon material the insulative layer 12 can be formed by the oxidizing the silicon material of the substrate 11 or be deposited by other means known in the art other materials that are equally acceptable for the conductive substrate 11 or the insulative layer 12 have already been discussed earlier once it is decided on the basic substrate structure then the subsequent steps can be the same for the illustration of the best mode to carry out this invention the substrate configuration of fig1 a will be used even though similar device would result if the substrate configuration of fig1 b is used as shown in fig2 on the anode conductive layer 13 a layer of grid insulator 15 could be made for example by oxidizing the doped polysilicon of layer 13 or by depositing an insulating glass layer to name a few.