Field-effect transistor

Patent metadata

Field	Value
Publication number	US-9406809-B2
Application number	US-201314024881-A
Country	US
Kind code	B2
Filing date	Sep 12, 2013
Priority date	Mar 18, 2011
Publication date	Aug 2, 2016
Grant date	Aug 2, 2016

Abstract

There is provided a field effect transistor having, on a substrate, at least a gate electrode, a gate insulating film, an active layer mainly containing an oxide semiconductor that contains at least one of In, Ga or Zn, a source electrode, and a drain electrode, the field effect transistor including: a heat diffusion layer, wherein, given that a thermal conductivity of the substrate is N sub (W/mK), a thermal conductivity of the heat diffusion layer is N kaku (W/mK), a film thickness of the heat diffusion layer is T (mm), a planar opening ratio of the heat diffusion layer is R (0≦R≦1), and S=T×R, the thermal conductivity N sub of the substrate satisfies the condition N sub <1.8, and the thermal conductivity N kaku of the heat diffusion layer satisfies the conditions N kaku >3.0×S^(−0.97×e^(−1.2×N sub )) and N kaku ≧N sub .

First claim

What is claimed is:

1. A field effect transistor having, on a resin substrate, at least a gate electrode, a gate insulating film, an active layer mainly containing an oxide semiconductor that contains at least one of In, Ga or Zn, a source electrode, and a drain electrode, the field effect transistor comprising:
a heat diffusion layer that is the same as or separate from the gate insulating film, and that is different than the gate electrode, the source electrode and the drain electrode,
wherein, given that a thermal conductivity of the resin substrate is N sub (W/mK), a thermal conductivity of the heat diffusion layer is N kaku (W/mK), a film thickness of the heat diffusion layer is T (mm), an opening ratio of the heat diffusion layer is R (0≦R≦1), and S=T×R,
the thermal conductivity N sub of the resin substrate satisfies the condition N sub <1.8, and
the thermal conductivity N kaku of the heat diffusion layer satisfies the conditions N kaku >3.0×S^(−0.97×e^(−1.2×N sub )) and N kaku ≧N sub .

2. The field effect transistor of claim 1 , wherein at least one layer or more of a thin film of less than or equal to 1 μm exists between the active layer and the heat diffusion layer.

3. The field effect transistor of claim 2 , wherein the heat diffusion layer is a nitride film containing at least one of Al or Ga.

4. The field effect transistor of claim 3 , wherein the transmittivity of the heat diffusion layer is greater than or equal to 70% with respect to light of a wavelength range of greater than or equal to 400 nm and less than or equal to 700 nm.

5. A display device comprising the field effect transistor of claim 1 .

6. A sensor comprising the field effect transistor of claim 1 .

7. A field effect transistor having, on a resin substrate, at least a gate electrode, a gate insulating film, an active layer mainly containing an oxide semiconductor that contains at least one of In, Ga or Zn, a source electrode, and a drain electrode, the field effect transistor comprising:
a heat diffusion layer that is the same as or separate from the gate insulating film, and that is different than the gate electrode, the source electrode and the drain electrode,
wherein, given that a thermal conductivity of the resin substrate is N sub (W/mK), a thermal conductivity of the heat diffusion layer is N kaku (W/mK), a film thickness of the heat diffusion layer is T (mm), an opening ratio of the heat diffusion layer is R (0≦R≦1), and S=T×R,
the thermal conductivity N sub of the resin substrate satisfies the condition N sub <0.5, and
the thermal conductivity N kaku of the heat diffusion layer satisfies the conditions N kaku >0.4×S^(−1.2×e^(−3.5×N sub )) and N kaku ≧N sub .

8. The field effect transistor of claim 7 , wherein at least one layer or more of a thin film of less than or equal to 1 μm exists between the active layer and the heat diffusion layer.

9. The field effect transistor of claim 8 , wherein the heat diffusion layer is a nitride film containing at least one of Al or Ga.

10. The field effect transistor of claim 9 , wherein the transmittivity of the heat diffusion layer is greater than or equal to 70% with respect to light of a wavelength range of greater than or equal to 400 nm and less than or equal to 700 nm.

11. A display device comprising the field effect transistor of claim 7 .

12. A sensor comprising the field effect transistor of claim 7 .

Assignees

• Fujifilm Corp

Inventors

• Umeda Kenichi
• Fujii Takamichi

Classifications

• H10D30/6704

  having supplementary regions or layers in the thin films or in the insulated bulk substrates for controlling properties of the device · CPC title

• H10D86/0251

  characterised by increasing the uniformity of device parameters · CPC title

• H10F30/29

  the devices being sensitive to radiation having very short wavelengths, e.g. X-rays, gamma-rays or corpuscular radiation · CPC title

• H10D30/6755 Primary

  Oxide semiconductors, e.g. zinc oxide, copper aluminium oxide or cadmium stannate · CPC title

• H10D30/6758

  characterised by the insulating substrates · CPC title