摘要:
A capacity layer is formed of non-doped polysilicon. Unlike capacity layers formed of an oxide film, generation of seams and the like can be suppressed and thereby a stable capacity layer can be formed. Moreover, polysilicon used as a capacity layer may be doped polysilicon, and an oxide film formed on the surface of the polysilicon also serves as a capacity film. Thus, provision of an insulated gate device featuring low capacity is made possible.
摘要:
A capacity layer is formed of non-doped polysilicon. Unlike capacity layers formed of an oxide film, generation of seams and the like can be suppressed and thereby a stable capacity layer can be formed. Moreover, polysilicon used as a capacity layer may be doped polysilicon, and an oxide film formed on the surface of the polysilicon also serves as a capacity film. Thus, provision of an insulated gate device featuring low capacity is made possible.
摘要:
In an embodiment of the present invention, after trenches, a gate oxide film and gate electrodes are formed, a channel layer is formed by plural high-acceleration ion implantations where acceleration voltages are different with one another. The channel layer is an impurity implanted layer on which diffusion by a heat treatment is not performed. The channel layer is allowed to have its impurity concentration substantially uniform in a depth-wise direction of the trenches, by implanting ions of the impurity at plural different times by use of a high-acceleration ion implantation system. Since a second region having almost no influence on a characteristic of the channel layer can be reduced, the channel layer having a minimum necessary depth can be obtained. The trenches are thus made shallow, and accordingly a capacitance can be reduced. Furthermore, an on resistance can be made lower by making an epitaxial layer thinner.
摘要:
In an embodiment of the present invention, after trenches, a gate oxide film and gate electrodes are formed, a channel layer is formed by plural high-acceleration ion implantations where acceleration voltages are different with one another. The channel layer is an impurity implanted layer on which diffusion by a heat treatment is not performed. The channel layer is allowed to have its impurity concentration substantially uniform in a depth-wise direction of the trenches, by implanting ions of the impurity at plural different times by use of a high-acceleration ion implantation system. Since a second region having almost no influence on a characteristic of the channel layer can be reduced, the channel layer having a minimum necessary depth can be obtained. The trenches are thus made shallow, and accordingly a capacitance can be reduced. Furthermore, an on resistance can be made lower by making an epitaxial layer thinner.
摘要:
A power MOSFET comprises: a semiconductor substrate 21 of a first conduction type; a drain layer 22 of the first conduction type and formed on a surface layer of the substrate; a gate insulating film 25 formed in a partial region on the drain layer 22; a gate electrode 26 formed on the gate insulating film 25; an insulating film 27 formed on the gate electrode; a side wall insulator 28 formed on side walls of the gate insulating film 25, the gate electrode 26, and the insulating film 27; a recess formed on the drain layer 22 and in a region other than a region where the gate electrode 25 and the side wall insulator 28 are formed; a channel layer 23 of a second conduction type opposite to the first conduction type and formed in a range from the region where the recess is formed to a vicinity of the region where the gate electrode 26 is formed; a source region layer 24 of the one conduction type and formed on the channel layer 23 outside the recess; and a wiring layer 29 formed to cover the channel layer 23 which is exposed through the recess, the side wall insulator 28, and the insulating film.
摘要:
An interlayer dielectric film is completely buried in a trench, and failures caused by step coverage is prevented because a source electrode can be formed substantially uniformly on an upper portion of a gate electrode. Also, in the processes of forming a source region, a body region and an interlayer dielectric film, only one mask is necessary so that the device size is reduced to account for placement error of only one mask alignment.
摘要:
A power MOSFET comprises: a semiconductor substrate 21 of a first conduction type; a drain layer 22 of the first conduction type and formed on a surface layer of the substrate; a gate insulating film 25 formed in a partial region on the drain layer 22; a gate electrode 26 formed on the gate insulating film 25; an insulating film 27 formed on the gate electrode; a side wall insulator 28 formed on side walls of the gate insulating film 25, the gate electrode 26, and the insulating film 27; a recess formed on the drain layer 22 and in a region other than a region where the gate electrode 25 and the side wall insulator 28 are formed; a channel layer 23 of a second conduction type opposite to the first conduction type and formed in a range from the region where the recess is formed to a vicinity of the region where the gate electrode 26 is formed; a source region layer 24 of the one conduction type and formed on the channel layer 23 outside the recess; and a wiring layer 29 formed to cover the channel layer 23 which is exposed through the recess, the side wall insulator 28, and the insulating film.
摘要:
An interlayer dielectric film is completely buried in a trench, and failures caused by step coverage is prevented because a source electrode can be formed substantially uniformly on an upper portion of a gate electrode. Also, in the processes of forming a source region, a body region and an interlayer dielectric film, only one mask is necessary so that the device size is reduced to account for placement error of only one mask alignment.
摘要:
A power MOSFET comprises: a semiconductor substrate 21 of a first conduction type; a drain layer 22 of the first conduction type and formed on a surface layer of the substrate; a gate insulating film 25 formed in a partial region on the drain layer 22; a gate electrode 26 formed on the gate insulating film 25; an insulating film 27 formed on the gate electrode; a side wall insulator 28 formed on side walls of the gate insulating film 25, the gate electrode 26, and the insulating film 27; a recess formed on the drain layer 22 and in a region other than a region where the gate electrode 25 and the side wall insulator 28 are formed; a channel layer 23 of a second conduction type opposite to the first conduction type and formed in a range from the region where the recess is formed to a vicinity of the region where the gate electrode 26 is formed; a source region layer 24 of the one conduction type and formed on the channel layer 23 outside the recess; and a wiring layer 29 formed to cover the channel layer 23 which is exposed through the recess, the side wall insulator 28, and the insulating film.
摘要:
Conventional power MOSFETs enables prevention of an inversion in a surrounding region surrounding the outer periphery of an element region by a wide annular layer and a wide sealed metal. Since, resultantly, the area of the surrounding region is large, increase in the element region has been restrained. A semiconductor device is hereby provided which has an inversion prevention region containing an MIS (MOS) structure. The width of polysilicon for the inversion prevention region is large enough to prevent an inversion since the area of an oxide film can be increased by the depth of the trench. By this, leakage current can be reduced even though the area of the region surrounding the outer periphery of the element region is not enlarged. In addition, since the element region is enlarged, on-state resistance of the MOSFET can be reduced.