Method of fabricating random access memory device having sidewall insulating layer on the laminate structure

A method of making a semiconductor device comprising:

• providing a semiconductor substrate of one conductivity type and having a top surface;
• forming doped regions having a dopant impurity of the other conductivity type in the semiconductor substrate of said one conductivity type in spaced relation to each other and opening onto the top surface of the semiconductor substrate;
• forming a first insulation layer on the top surface of the semiconductor substrate of said one conductivity type;
• forming a first layer of electrically conductive material over the first insulation layer;
• forming a second insulation layer over the first electrically conductive layer;
• defining laminate structures from the first layer of electrically conductive material and the second insulating layer so as to provide at least respective first and second laminate structures of electrically conductive material and overlying insulation material in stacked relationship on the first insulation layer and spaced from each other to provide an exposed portion of the first insulation layer overlying the semiconductor substrate;
• forming a third insulation layer covering only the sides of the first layer of electrically conductive material included in the first and second laminate structures;
• forming a fourth insulation layer overlying the first and second laminate structures and covering the sides thereof so as to overlie said third insulation layer and lying between the first and second laminate structures so as to cover the exposed portion of the first insulation layer;
• removing the portion of the fourth insulation layer lying between the first and second laminate structures, and also removing the underlying portion of the first insulation layer to expose a portion of at least one of the doped regions of the other conductivity type in the semiconductor substrate of said one conductivity type and opening onto the top surface thereof;
• and
• forming a second layer of electrically conductive material over the second insulation layer included in the first and second laminate structures and into the space between the first and second laminate structures to connect with the at least one exposed doped region of the other conductivity type located therebetween.