In a semiconductor device having an SOI structure and a method of manufacturing the same, influence by a parasitic transistor can be prevented, and no disadvantage is caused in connection with a manufacturing process. In this semiconductor device, an upper side portion of a semiconductor layer is rounded. Thereby, concentration of an electric field at the upper side portion of the semiconductor layer can be prevented. As a result, lowering of a threshold voltage of a parasitic transistor can be prevented, so that the parasitic transistor does not adversely affect subthreshold characteristics of a regular transistor. Owing to provision of a concavity of a U-shaped section, generation of etching residue can be prevented when etching a gate electrode for patterning the same. Thereby, a disadvantage is not caused in connection with the manufacturing process.
A semiconductor substrate and a method of fabricating a semiconductor device are provided. An oxide film (13) is formed by oxidizing an edge section and a lower major surface of an SOI substrate (10). This oxidizing step is performed in a manner similar to LOCOS (Local Oxide of Silicon) oxidation by using an oxide film (11) exposed on the edge section and lower major surface of the SOI substrate (10) as an underlying oxide film. Then, the thickness of the oxide film (13) is greater than that of the oxide film (11) on the edge section and lower major surface of the SOI substrate (10). The semiconductor substrate prevents particles of dust from being produced at the edge thereof.
A semiconductor device includes a semiconductor layer formed on part of an insulating layer. The semiconductor layer includes a diffusion region and a channel region. The insulating layer is etched so that the semiconductor layer is separated from the insulating layer below at least part of the diffusion region. The space left below this part of the semiconductor layer is filled by an etch stop film that also covers the side surfaces of the insulating layer. The etch stop film prevents contact holes targeted at the diffusion region from penetrating the insulating layer due to alignment error or defects in the semiconductor layer. Since the etch stop film is not present below the channel region, the electrical characteristics of the semiconductor device are not altered.
In a large-sized substrate for use in liquid crystal display devices, microcracks in a gate insulating film are prevented from being generated, whereby warpage of the substrate is suppressed. In order to solve the problems, in thin film transistors arrayed on a glass substrate, the gate insulating film is made thicker only in the portion that is directly under a gate line layer.
An integrated circuit includes a plurality of transistors formed to include insulative punchthrough regions. Each of the plurality of transistors includes a channel formed upon a substrate, an insulative punchthrough region formed below the channel, a source formed upon the insulative punchthrough region residing adjacent a first end of the channel, a drain formed upon the insulative punchthrough region residing adjacent a second end of the channel, a gate oxide formed above the channel and a gate conductor formed above the gate oxide. Isolation regions may also be formed in the substrate that have an etch stop defination that was formed upon formation of the insulative punchthrough region. A voltage threshold region may be formed between the gate oxide and the channel and lightly doped regions may be formed adjacent the channel. The insulative punchthrough region may be and oxide layer formed within the substrate in an oxygen implant step that also formed the etch stop defination. The transistors and other circuit elements formed in the substrate may be interconnected to form an integrated circuit.
The invention relates to a process for the treatment of substrates (1) for microelectronics or optoelectronics comprising a working layer (6) at least partially composed of an oxidizable material on at least one of their faces, this process comprising: a first sacrificial oxidation stage for removing material constituting the working layer (6) over a certain surface thickness of each substrate (1), a stage of polishing (200) the face which has been subjected to the first sacrificial oxidation stage (100), and a second sacrificial oxidation stage for again removing material constituting the working layer (6) on the polished face (17).
