1. A silicon carbide (SiC) semiconductor device, comprising:
a gate oxide layer disposed on top of a SiC semiconductor layer; and
a gate electrode comprising a tapered sidewall, wherein the gate electrode comprises a polysilicon layer disposed on top of the gate oxide layer and a metal silicide layer disposed on top of the polysilicon layer.
2. The semiconductor device of claim 1, wherein at least a portion of the tapered sidewall of the gate electrode is disposed at an angle relative to a surface of the semiconductor device, and wherein the angle is between approximately 65 degrees and approximately 85 degrees.
3. The semiconductor device of claim 1, comprising a rounded photoresist layer disposed on top of the gate electrode.
4. The semiconductor device of claim 1, wherein the metal silicide layer comprises one or more of tantalum silicide, nickel silicide, cobalt silicide, titanium silicide, molybdenum silicide, tungsten silicide, niobium silicide, hafnium silicide, zirconium silicide, vanadium silicide, chromium silicide, or platinum silicide.
5. The semiconductor device of claim 1, wherein a width of the metal silicide layer is approximately equal to a top width of the polysilicon layer.
6. The semiconductor device of claim 1, wherein the metal silicide layer comprises tantalum silicide.
7. The semiconductor device of claim 1, wherein the tantalum silicide layer comprises between approximately 2 and 4 silicon atoms for each tantalum atom.
8. The semiconductor device of claim 7, wherein the tantalum silicide layer comprises approximately 3.3 silicon atoms for each tantalum atom.
9. The semiconductor device of claim 7, wherein the tantalum silicide layer comprises approximately 2.7 silicon atoms for each tantalum atom.
10. The semiconductor device of claim 1, wherein a portion of the oxide layer disposed near the tapered sidewall of the gate electrode is substantially free from trench defects and etch byproducts.
11. A silicon carbide (SiC) semiconductor device, comprising:
a gate electrode comprising a polysilicon layer having a substantially tapered edge and a metal silicide layer having a substantially vertical edge; and
a gate oxide layer comprising a first portion disposed directly under the gate electrode and a second portion not disposed directly under the gate electrode, wherein the second portion of the gate oxide layer is substantially free from microtrenching and inorganic residue near the tapered edge of the polysilicon layer.
12. The semiconductor device of claim 11, wherein the tapered edge is disposed at an first angle relative to a surface of the semiconductor device, and wherein the first angle is between approximately 65 degrees and approximately 85 degrees, and wherein the substantially vertical edge is disposed at a second angle relative to the surface of the semiconductor device, and wherein the second angle is between approximately 80 degrees and approximately 100 degrees.
13. The semiconductor device of claim 11, wherein a first portion of the gate oxide layer has a first thickness of approximately 500 angstroms, and wherein a second portion of the gate oxide layer has a second thickness between approximately 275 angstroms and approximately 400 angstroms.
14. The semiconductor device of claim 11, wherein a second portion of the gate oxide layer is between approximately 20% and approximately 35% thinner than the first portion of the gate oxide layer.
15. The semiconductor device of claim 11, wherein a second portion of the gate oxide layer is between approximately 75 angstroms and approximately 200 angstroms thinner than the first portion of the gate oxide layer.
16. An electrical device, comprising:
a silicon carbide (SiC) semiconductor device, comprising:
a gate electrode comprising a polysilicon layer having a substantially tapered edge and a tantalum silicide layer having a substantially vertical edge; and
a gate oxide layer comprising a first portion disposed under the gate electrode and a second portion not disposed under the gate electrode, wherein the second portion has a thickness that is between approximately 20% and approximately 40% a thickness of the first portion.
17. The electrical device of claim 16, wherein the thickness of the first portion is approximately 475 angstroms, and wherein the thickness of the second portion is between approximately 300 angstroms and approximately 375 angstroms.
18. The electrical device of claim 16, wherein a second portion of the gate oxide layer is between approximately 100 angstroms and approximately 175 angstroms thinner than the first portion of the gate oxide layer.
19. The electrical device of claim 16, wherein the second portion of the gate oxide layer is substantially free of microtrenching and inorganic etching byproducts near the tapered edge of the polysilicon layer
20. The electrical device of claim 16, wherein the electronic device is a power conversion device.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A luminance control device that controls luminance of a light source as backlight of a display panel, comprising:
a picture luminance detector for detecting luminance of an input picture signal;
a picture luminance storage for storing a plurality of luminance detected before the luminance of the picture signal detected by the picture luminance detector; and,
a processor that detects variability that indicates intensity of variation of the luminance of the picture signal based on the plurality of luminance stored in the picture luminance storage and controls luminance of a light source based on the luminance of the picture signal detected by the picture luminance detector and the variability,
wherein the processor calculates a directional characteristic of the variation of the picture luminance, and increases the amount of reduction in the light source luminance when the directional characteristic of the variation is on a downward trend and suppresses the amount of reduction in the light source luminance when the directional characteristic of the variation is on an upward trend.
2. A luminance control device that controls luminance of a light source as backlight of a display panel, comprising:
a picture luminance detector for detecting luminance of an input picture signal;
a picture luminance storage for storing a plurality of luminance detected before the luminance of the picture signal detected by the picture luminance detector; and,
a processor that detects variability that indicates intensity of variation of the luminance of the picture signal based on the plurality of luminance stored in the picture luminance storage and controls luminance of a light source based on the luminance of the picture signal detected by the picture luminance detector and the variability,
wherein the processor calculates a directional characteristic of the variation of the picture luminance, and increases the amount of reduction in the light source luminance when a progress of a directional characteristic of the variation changes from an upward trend to a downward trend.
3. A luminance control device that controls luminance of a light source as backlight of a display panel, comprising:
a picture luminance detector for detecting luminance of an input picture signal;
a picture luminance storage for storing a plurality of luminance detected before the luminance of the picture signal detected by the picture luminance detector; and,
a processor that detects variability that indicates intensity of variation of the luminance of the picture signal based on the plurality of luminance stored in the picture luminance storage and controls luminance of a light source based on the luminance of the picture signal detected by the picture luminance detector and the variability,
wherein the processor calculates a directional characteristic of the variation of the picture luminance, and suppresses the amount of reduction in the light source luminance when a directional characteristic of the variation progresses in an order of a downward trend, a non-directional trend and an upward trend.
4. A luminance control method for controlling luminance of a light source as backlight of a display panel, comprising:
detecting luminance of an input picture signal;
storing step for storing a plurality of luminance detected before the luminance of the picture signal detected at the picture luminance detecting step;
detecting variability that indicates intensity of variation of the luminance of the picture signal based on the plurality of luminance stored at the picture luminance storing step and controls luminance of a light source based on the luminance of the picture signal detected at the picture luminance detecting step and the variability;
calculating a directional characteristic of the variation of the picture luminance, and changing the amount of reduction in the light source luminance, wherein the changing the amount of reduction in the light source luminance is selected from the group consisting of
(a) increasing the amount of reduction in the light source luminance when the directional characteristic of the variation is on a downward trend and suppressing the amount of reduction in the light source luminance when the directional characteristic of the variation is on an upward trend,
(b) increasing the amount of reduction in the light source luminance when a progress of a directional characteristic of the variation changes from an upward trend to a downward trend, and
(c) suppressing the amount of reduction in the light source luminance when a directional characteristic of the variation progresses in an order of a downward trend, a non-directional trend and an upward trend.
5. A non-transitory luminance control program for causing a control device to execute a luminance control method according to claim 4.