التفاصيل البيبلوغرافية
| العنوان: |
PHOTO-FIELD EFFECT TRANSISTOR AND ITS PRODUCTION METHOD |
| Document Number: |
20110001166 |
| تاريخ النشر: |
January 6, 2011 |
| Appl. No: |
12/735795 |
| Application Filed: |
February 17, 2009 |
| مستخلص: |
This invention provides a photo-FET, in which a FET part and photodiode part are stacked, and the FET part and photodiode part are optimized independently in design and operational bias conditions. The semiconductor layer serving as a photo-absorption layer (41) is formed on the cathode semiconductor layer (10) of a photodiode part (50). An electron barrier layer (40) with a wider bandgap semiconductor than a photo-absorption layer (41), which also serves as an anode layer of a photodiode part (50), is formed on a photo-absorption layer (41). The channel layer (15) which constitutes the channel regions of the FET part is formed with a narrower bandgap semiconductor than an electron barrier layer (40) on an electron barrier layer (40). The hole barrier layer (16) with a bandgap wider than the semiconductor which constitutes a channel layer (15) is formed on a channel layer (15). The source electrode (30) and drain electrode (32) which are separated each others, are formed on a hole barrier layer (16). The holes injected into the channel layer (15) by light illumination through the electron barrier layer (40) from the photo-absorption layer (41) are confined with the hole barrier layer (16). And the electrons in a channel layer (15) are confined with the electron barrier layer (40) into the channel layer (15), respectively. |
| Inventors: |
Ogura, Mutsuo (Ibaraki, JP) |
| Assignees: |
National Instituteof Advanced Industrial Science and Technology (Tokyo, JP) |
| Claim: |
1. A photo-FET wherein an FET part is stacked on a photodiode part, said photo-FET comprising at least: a semiconductor layer forming a photo-absorption layer of said photodiode part, which is formed on a cathode semiconductor layer of said photodiode part; an electron barrier layer, which is formed on said photo-absorption layer and forms a semiconductor layer with a bandgap wider than that of said photo-absorption layer, and works as an anode layer of said photodiode; a channel layer, which is formed on said electron barrier layer and forms a semiconductor layer with a bandgap narrower than that of said electron barrier layer, said channel layer forming a channel region of said FET part; a hole barrier layer, which is formed on said channel layer and comprises a semiconductor with a bandgap wider than that of said channel layer; and a source electrode and a drain electrode, formed on said hole barrier layer, which are separated from each other; wherein holes injected into said channel layer by light illumination through said electron barrier layer from said photo-absorption layer are confined by said hole barrier layer into the channel layer, and electrons in the channel layer are also confined by said electron barrier layer into this channel layer. |
| Claim: |
2. A photo-FET according to claim 1, wherein said channel layer is formed in a mesa structure with an exposed sidewall; and an impurity diffusion layer in which conductive impurities with polarity opposite to that of the channel layer are doped is formed at the exposed sidewall of said channel layer and an exposed surface at a portion surrounding the mesa structure in the electron barrier layer underneath the mesa structure. |
| Claim: |
3. A photo-FET according to claim 1, wherein said cathode semiconductor layer includes a bandgap wider than that of the photo-absorption layer; said electron barrier layer and said photo-absorption layer are formed in a second mesa structure with exposed sidewalls; and an impurity diffusion layer in which conductive impurities with polarity opposite to that of the photo-absorption layer are doped is formed at the exposed sidewalls of said electron barrier layer and said photo-absorption layer, and an exposed surface at a portion surrounding the second mesa structure in the cathode semiconductor layer underneath said second mesa structure. |
| Claim: |
4. A photo-FET according to claim 1, wherein said cathode semiconductor layer is an n-type semiconductor layer, said photo-absorption layer is either an n-type or non-doped semiconductor, said electron barrier layer is a p-type semiconductor, said channel layer is either an n-type or a non-doped semiconductor, and the hole barrier layer is either an n-type or non-doped semiconductor. |
| Claim: |
5. A photo-FET according to claim 1, wherein said cathode semiconductor layer is an n-type semiconductor layer, said photo-absorption layer is either an n-type or non-doped semiconductor with p-type impurity doped at a surface, said electron barrier layer in contact with said surface of said photo-absorption layer is a non-doped semiconductor, said channel layer is either an n-type or non-doped semiconductor, and said hole barrier layer is an n-type or non-doped semiconductor. |
| Claim: |
6. A photo-FET according to claim 1, wherein said cathode semiconductor layer comprises a substrate, a buffer layer formed on said substrate, and a step graded layer formed on said buffer layer in contact with said electron barrier layer. |
| Claim: |
7. A photo-FET according to claim 1, wherein said channel layer includes three stacked layers comprising a step graded layer in contact with said electron barrier layer, a primary channel layer above said step graded layer, and another step graded layer above said primary channel layer and under the said hole barrier layer. |
| Claim: |
8. A photo-FET according to claim 1, wherein a p-n junction gate electrode is formed between said source electrode and said drain electrode in contact with said hole barrier layer. |
| Claim: |
9. A photo-FET according to claim 1, wherein a Schottky junction gate electrode is formed between said source electrode and said drain electrode in contact with said hole barrier layer. |
| Claim: |
10. A photo-FET according to claim 1, wherein an area of said channel layer is smaller in plan than an area of said photo-absorption layer. |
| Claim: |
11. A photo-FET according to claim 1, wherein said source electrode and said drain electrode are arranged in a concentric pattern. |
| Claim: |
12. A photo-FET according to claim 1, wherein said source electrode, said gate electrode and said drain electrode are arranged in a concentric pattern. |
| Claim: |
13. A production method of a photo-FET wherein a photo-FET part is stacked on a photodiode part, comprising: an epitaxial growth process of forming a semiconductor layer, serving as a photo-absorption layer of said photodiode part, on a cathode semiconductor layer constituting a cathode of the photodiode part; an electron barrier layer on the photo-diode part, serving as an anode layer of said photo-diode part and constituting a semiconductor with a bandgap wider than that the photo-absorption layer; and a channel layer on the electron barrier layer constituting a channel region of said photo-FET and comprising a semiconductor with a bandgap narrower than that of the electron barrier layer; and a hole barrier layer, on said channel layer, comprising a semiconductor with a bandgap wider than that of the semiconductor constituting said channel layer, sequentially; a process of forming a source electrode and a drain electrode, which are separated on said hole barrier layer; and a process of cutting said channel layer in a predetermined configuration as said electron barrier layer as an etch stop layer. |
| Current U.S. Class: |
257/187 |
| Current International Class: |
01; 01 |
| رقم الانضمام: |
edspap.20110001166 |
| قاعدة البيانات: |
USPTO Patent Applications |