1. A railroad tank car comprising:
(a) a cargo tank for containing fluid cargo and having an elongate generally cylindrical configuration including a horizontal central axis, a pair of opposite ends, and a top;
(b) an opening defined in the top of the tank;
(c) a nozzle extending from the opening and having a portion located above the top of the cargo tank;
(d) a closure member associated with the nozzle;
(e) a protective structure attached to the top of the tank, the protective structure at least partially enclosing the nozzle and the closure member, the protective structure including a pair of laterally-separated side plates located on opposite lateral sides of the opening and a skid structure supported by and extending laterally between the side plates, the skid structure extending longitudinally of the railcar and including an upwardly-inclined end portion extending longitudinally of the railcar on a sloping angle, from a location adjacent the top of the tank and spaced longitudinally apart from the opening, to an uppermost part of the skid structure;
(f) a central portion of the protective structure extending longitudinally and located above the closure member;
(g) a transversely-oriented reinforcing diaphragm interconnecting the side plates with each other; and
(h) an access opening defined through the central portion of the skid structure in a location aligned with the closure member, and wherein at least one of the side plates defines an opening aligned with a valve operating mechanism, the opening having a shape admitting introduction of a valve-operating handle so as to mate with the valve operating mechanism only when the valve operating mechanism is in a predetermined position.
2. The railroad car of claim 1 including a pair of elongate mounting pads attached to the cargo tank, the side plates each being attached to and extending along a respective one of the mounting pads.
3. The railroad car of claim 1 wherein the end portion of the skid structure is a plate welded to the diaphragm and to the side plates.
4. The railroad car of claim 1 wherein the closure member is a valve mounting plate.
5. The railroad car of claim 1 including a lid movably attached to the central portion of the protective structure and covering at least a portion of the access opening in the central portion and wherein the lid includes an extension aligned with the opening defined in the side plate so as to hold a valve-operating handle in a predetermined position when the lid is in a closed position.
6. A railroad tank car comprising:
(a) a cargo tank for containing fluid cargo and having an elongate generally cylindrical configuration including a horizontal central axis, a pair of opposite ends, and a top;
(b) an opening defined in the top of the tank;
(c) a nozzle extending from the opening and having a portion located above the top of the cargo tank;
(d) a closure member associated with the nozzle;
(e) a protective structure attached to the top of the tank, the protective structure at least partially enclosing the nozzle and the closure member, the protective structure including a pair of laterally-separated side plates located on opposite lateral sides of the opening and a skid structure supported by and extending laterally between the side plates, the skid structure extending longitudinally of the railcar and including an upwardly-inclined end portion extending longitudinally of the railcar on a sloping angle, from a location adjacent the top of the tank and spaced longitudinally apart from the opening, to an uppermost part of the skid structure;
(f) central portion of the protective structure extending longitudinally and located above the closure member;
(g) a transversely-oriented reinforcing diaphragm interconnecting the side plates with each other;
(h) an access opening defined through the central portion of the skid structure in a location aligned with the closure member;
(i) wherein at least one of the side plates defines an opening aligned with a valve operating mechanism; and
(j) a lid movably attached to the central portion of the skid structure and covering at least a portion of the access opening in the central portion, and wherein the lid includes an extension aligned with the opening in the side plate so as to hold a valve operating handle in a predetermined position when the lid is in a closed position.
7. A railroad tank car comprising:
(a) a cargo tank for containing fluid cargo and having an elongate generally cylindrical configuration including a horizontal central axis, a pair of opposite ends, and a top;
(b) an opening defined in the top of the tank;
(c) a nozzle extending from the opening and having a portion located above the top of the cargo tank
(d) a closure member associated with the nozzle;
(e) a protective structure attached to the top of the tank, the protective structure at least partially enclosing the nozzle and the closure member, the protective structure including a pair of laterally-separated side plates located on opposite lateral sides of the opening and a skid structure supported by and extending laterally between the side plates, the skid structure extending longitudinally of the railcar and including an upwardly-inclined end portion extending longitudinally of the railcar on a sloping angle, from a location adjacent the top of the tank and spaced longitudinally apart from the opening, to an uppermost part of the skid structure;
(f) a central portion of the protective structure extending longitudinally and located above the closure member;
(g) a transversely-oriented reinforcing diaphragm interconnecting the side plates with each other; and
(h) an access opening defined through the central portion of the skid structure in a location aligned with the closure member; and wherein a pressure relief safety valve is located on the top of the tank at a location longitudinally spaced apart from the opening defined in the top of the tank, the upwardly-inclined end portion of the protective structure at least partially surrounding the pressure relief safety valve.
8. The railroad car of claim 7 wherein the opening in the top of the tank is a manway.
9. The railroad car of claim 7 including a pair of elongate mounting pads attached to the cargo tank, the side plates each being attached to and extending along a respective one of the mounting pads.
10. A railroad tank car comprising:
(a) a cargo tank for containing fluid cargo and having an elongate generally cylindrical configuration including a horizontal central axis, a pair of opposite ends, and a top;
(b) an opening defined in the top of the tank;
(c) a nozzle extending from the opening and having a portion located above the top of the cargo tank;
(d) a closure member associated with the nozzle;
(e) a protective structure attached to the top of the tank, the protective structure at least partially enclosing the nozzle and the closure member, the protective structure including a pair of laterally-separated side plates located on opposite lateral sides of the opening and a skid structure supported by and extending laterally between the side plates, the skid structure extending longitudinally of the railcar and including an upwardly-inclined end portion extending longitudinally of the railcar on a sloping angle, from a location adjacent the top of the tank and spaced longitudinally apart from the opening, to an uppermost part of the skid structure;
(f) a central portion of the protective structure extending longitudinally and located above the closure member;
(g) a transversely-oriented reinforcing diaphragm interconnecting the side plates with each other;
(h) an access opening defined through the central portion of the skid structure in a location aligned with the closure member; and
(i) a pressure relief safety valve located on the top of the tank at a location longitudinally spaced apart from the opening defined in the top of the tank, the upwardly-inclined end portion of the protective structure defining a pressure relief opening above the pressure relief safety valve.
The claims below are in addition to those above.
All refrences to claims which appear below refer to the numbering after this setence.
1. A method of forming a portion of a memory device, comprising:
forming a dielectric liner overlying and in direct contact with a portion of a trench that extends into a substrate below an upper surface of the substrate;
forming a first dielectric plug in the portion of a trench that extends into the substrate below the upper surface of the substrate so that an upper surface of the first dielectric plug is recessed below the upper surface of the substrate, the first dielectric plug comprising a layer of a first dielectric material overlying and in direct contact with the dielectric liner and a layer of a second dielectric material formed on the layer of the first dielectric material so that the upper surface of the first dielectric plug comprises an upper surface of the layer of the second dielectric material and a portion of the layer of the first dielectric material coplanar with the upper surface of the layer of the second dielectric material; and
forming a second dielectric plug of a third dielectric material on the upper surface of the first dielectric plug so that the second dielectric plug extends from the upper surface of the first dielectric plug through another portion of the trench that extends above the upper surface of the substrate and that passes through a layer of a fourth dielectric material overlying the upper surface of the substrate and a conductive layer overlying the layer of fourth dielectric material, wherein the second dielectric plug contacts a portion of the layer of fourth dielectric material and a portion of the conductive layer.
2. The method of claim 1, wherein forming the second dielectric plug comprises forming a portion of the second dielectric plug on the dielectric liner.
3. The method of claim 1, wherein the second dielectric plug is a high-density-plasma oxide.
4. The method of claim 1, wherein forming the first dielectric plug further comprises curing the layer of second dielectric material.
5. The method of claim 4, wherein curing the layer of second dielectric material comprises an oxidation process.
6. The method of claim 1 further comprises, after forming the second dielectric plug:
forming a layer of fifth dielectric material overlying the conductive layer; and
forming another conductive layer overlying the layer of fifth dielectric material.
7. A method of forming a portion of a memory device, comprising:
forming a first dielectric plug in a portion of a trench that extends into a substrate below an upper surface of the substrate so that an upper surface of the first dielectric plug is recessed below the upper surface of the substrate, the first dielectric plug comprising a layer of a first dielectric material and a layer of a second dielectric material formed on the layer of the first dielectric material; and
forming a second dielectric plug of a third dielectric material on the upper surface of the first dielectric plug so that the second dielectric plug extends from the upper surface of the first dielectric plug through another portion of the trench that extends above the upper surface of the substrate and that passes through a layer of a fourth dielectric material overlying the upper surface of the substrate and a first conductive layer overlying the layer of fourth dielectric material, wherein the second dielectric plug contacts a portion of the layer of fourth dielectric material and a portion of the conductive layer; and
after forming the second dielectric plug:
forming a layer of fifth dielectric material overlying the conductive layer so that an upper surface of the fifth dielectric material is located at a depth below an upper surface of the second dielectric plug; and
forming a second conductive layer overlying the layer of fifth dielectric material.
8. A method of forming a portion of a memory device, comprising:
lining a first portion of a trench that extends into a substrate below an upper surface of the substrate with a first dielectric layer by forming the first dielectric layer on the substrate;
forming a second dielectric layer in the first portion of the trench on the first dielectric layer and in a second portion of the trench that extends above the upper surface of the substrate and that passes through a tunnel dielectric layer overlying the upper surface of the substrate and a floating gate layer overlying the tunnel dielectric layer;
forming a fourth dielectric layer on the second dielectric layer so that the fourth dielectric layer fills a portion of the first portion trench and so that an upper surface of the fourth dielectric layer is located below the upper surface of the substrate;
removing a portion of the second dielectric layer to a level of the upper surface of the fourth dielectric layer to expose a portion of the first dielectric layer located between the upper surface of the fourth dielectric layer and the upper surface of the substrate; and
forming a fifth dielectric layer on the upper surface of the fourth dielectric layer and on the exposed portion of the first dielectric layer so as to fill a remaining portion of the first portion of the trench and to fill the second portion of the trench so that a portion of the fifth dielectric layer filling the second portion of the trench contacts a portion of the tunnel dielectric layer overlying the upper surface of the substrate and a portion of the floating gate layer overlying the tunnel dielectric layer;
after forming the fifth dielectric layer:
forming an intergate dielectric layer overlying the floating gate layer so that an upper surface of the intergate dielectric layer is located at a depth below an upper surface of the fifth dielectric layer; and
forming a control gate overlying the intergate dielectric layer.
9. A method of forming a portion of a memory device, comprising:
lining a first portion of a trench that extends into a substrate below an upper surface of the substrate with a first dielectric layer by forming the first dielectric layer overlying and in direct contact with the substrate;
forming a second dielectric layer in the first portion of the trench overlying and in direct contact with the first dielectric layer and in a second portion of the trench that extends above the upper surface of the substrate and that passes through a third dielectric layer overlying the upper surface of the substrate and a conductive layer overlying the third dielectric layer;
forming a fourth dielectric layer on the second dielectric layer so that the fourth dielectric layer fills a portion of the first portion trench and so that an upper surface of the fourth dielectric layer is located below the upper surface of the substrate;
removing a portion of the second dielectric layer to a level of the upper surface of the fourth dielectric layer to expose a portion of the first dielectric layer located between the upper surface of the fourth dielectric layer and the upper surface of the substrate, and such that a portion of the second dielectric layer is coplanar with the upper surface of the fourth dielectric layer; and
forming a fifth dielectric layer on the upper surface of the fourth dielectric layer and on the exposed portion of the first dielectric layer so as to fill a remaining portion of the first portion of the trench and to fill the second portion of the trench so that a portion of the fifth dielectric layer filling the second portion of the trench contacts a portion of the third dielectric layer overlying the upper surface of the substrate and a portion of the conductive layer overlying the third dielectric layer.
10. The method of claim 9, wherein forming the fourth dielectric layer comprises:
filling the trench with the fourth dielectric layer to a level above the upper surface of the substrate; and
recessing the fourth dielectric layer so that the upper surface of the fourth dielectric layer is located below the upper surface of the substrate.
11. The method on claim 10 further comprises curing the fourth dielectric layer before recessing the fourth dielectric layer.
12. The method of claim 9, wherein forming the second dielectric layer comprises forming a portion of the second dielectric layer overlying an upper surface of the conductive layer.
13. The method of claim 12, wherein forming the portion of the second dielectric layer overlying the upper surface of the conductive layer comprises forming the second dielectric layer on an upper surface of a hard mask layer formed overlying the upper surface of the conductive layer.
14. The method of claim 9, wherein the third dielectric layer is a tunnel dielectric layer and the conductive layer is a floating gate layer, and further comprising after forming the fifth dielectric layer:
forming an intergate dielectric layer overlying the floating gate layer; and
forming a control gate overlying the intergate dielectric layer.