A field emission display includes a substrate and a plurality of emitters formed on columns on the substrate. The display also includes a porous dielectric layer formed on the substrate and the columns. The porous dielectric layer has an opening formed about each of the emitters and has a thickness substantially equal to a height of the emitters above the substrate. The porous dielectric layer may be formed by oxidation of porous polycrystalline silicon. The display also includes an extraction grid formed substantially in a plane defined by respective tips of the plurality of emitters and having an opening surrounding each tip of a respective one of the emitters. The display further includes a cathodoluminescent-coated faceplate having a planar surface formed parallel to and near the plane of tips of the plurality of emitters. The porous dielectric layer results in columns having less capacitance compared to prior art displays. Accordingly, less electrical power is required to charge and discharge the columns in order to drive the emitters. As a result, the display is able to form luminous images while consuming reduced electrical power compared to prior art displays.

Field emission display having reduced power requirements and method

A semiconductor structure including a trench formed in a substrate and a buried isolation collar that extends about sidewalls of the trench. The buried isolation collar is constituted by an insulator formed from a buried porous region of substrate material. The porous region is formed from a buried doped region defined using masking and ion implantation or by masking the trench sidewalls and using dopant diffusion. Advantageously, the porous region is transformed to an oxide insulator by an oxidation process. The semiconductor structure may be a storage capacitor of a memory cell further having a buried plate about the trench and a capacitor node inside the trench that is separated from the buried plate by a node dielectric formed on the trench sidewalls.

Methods for forming semiconductor structures with buried isolation collars and semiconductor structures formed by these methods

A method is provided for manufacturing semiconductor structures having dielectrically isolated silicon regions on one side of a silicon body. This is accomplished by forming in the silicon body a set of buried regions and a set of surface regions having characteristics which make them anodically etch slower than the remaining portion of the silicon body. These two sets of regions define portions in the silicon body which are anodically etched to form porous silicon regions which are oxidized to form an isolation structure that isolates the silicon surface regions from each other and the remaining portion of the silicon body. Typically in a P-type silicon body the buried and surface regions are N-type regions formed through ion implantation. Using these N-type regions to control the exposure of the P-type material to the anodic etching solution and the formation of the porous silicon regions, a structure is obtained wherein surface monocrystalline silicon regions are isolated from the rest of the silicon body by a uniform layer of silicon dioxide having a predetermined thickness.

Method of manufacturing semiconductor structures having an oxidized porous silicon isolation layer

A method of forming a multiple level porous silicon substrate for semiconductor integrated circuits including anodizing non-porous silicon layers of a multi-layer silicon substrate to form multiple levels of porous silicon. At least one porous silicon layer is then oxidized to form an insulating layer and at least one other layer of porous silicon beneath the insulating layer is metallized to form a buried conductive layer. Preferably the insulating layer and conductive layer are separated by an anodization barrier formed of non-porous silicon. By etching through the anodization barrier and subsequently forming a metallized conductive layer, a fully or partially insulated buried conductor may be fabricated under single crystal silicon.

Formation of multiple levels of porous silicon for buried insulators and conductors in silicon device technologies

The present invention provides a method of fabricating fully dielectric isolated silicon (FDIS) by anodizing a buried doped silicon layer through trenches formed between active areas to form a porous silicon layer; oxidizing the porous silicon layer through the trenches to form a buried oxide layer; and by depositing a dielectric in the trenches. The process begins by forming a buried doped layer in a silicon substrate defining a silicon top layer over the conductive buried doped layer. The silicon top layer and the buried doped layer are patterned to form trenches that extend into but not through the buried doped layer. The trenches define isolated silicon regions. The buried doped layer is anodized to form a porous silicon layer. The porous silicon layer is converted into a buried oxide layer by oxidation. The oxidation step also forms a liner oxide layer on the tops and sidewalls of the isolated silicon regions. Ion species can optionally be implanted into the sidewalls of the isolated silicon regions to form lightly doped regions to act as channel stops. A fill oxide layer is deposited over the buried oxide layer and the liner oxide layer. The fill oxide layer and the liner oxide layer are removed down to the level of the top of the isolated silicon regions thereby exposing a fully dielectric isolated silicon.

Method for fabricating fully dielectric isolated silicon (FDIS)

A semiconductor device, such as a transistor, integrated circuit or the like, having a pattern of oxidized and densified porous silicon regions extending onto one of its major surfaces for isolating regions of the semiconductor is manufacturable by a relatively simple process. The process involves forming porous silicon regions in the surface of the semiconductor body such as a silicon wafer, in the areas where dielectric isolation between semiconductor devices is desired. The porous silicon regions are then oxidized at a temperature sufficient to completely oxidize the porous silicon. The oxidiation is such that the oxidized porous silicon extends above the surface of the semiconductor wafer. The oxidized porous silicon regions are then subjected to a temperature higher than the oxidizing temperature utilized in the previous step to cause the densification of the oxidized porous silicon regions. The result of this densification step is the collapse of the porous oxide to a dense structure which is substantially planar with the surface of the semiconductor wafer. This densified silicon dioxide structure has an etch rate which is substantially the same as thermally grown silicon dioxide.

Broadie Robert Wallace

Papers

Integrated circuit isolation structure and method for producing the isolation structure

Integrated circuit isolation structure

Verfahren zum herstellen von oxydiertes halbleitermaterial enthaltenden strukturen

Dispositifs a semiconducteurs isoles par des regions de sio2 encastrees et procede de fabrication desdits dispositifs