ASYMMETRICAL BLOCKING BIDIRECTIONAL GALLIUM NITRIDE SWITCH
A high electron mobility transistor (HEMT)gallium nitride (GaN) bidirectional blocking device includes a hetero-j unction structure comprises a first semiconductor layer interfacing a second semiconductor layer of two different band gaps thus generating an interface layer as a two-dimensional electron gas (2 DEG) layer. The HEMT GaN bidirectional blocking device further includes a first source/drain electrode and a second source/drain electrode disposed on two opposite sides of a gate electrode disposed on top of said hetero-junction structure for controlling a current flow between the first and second source/drain electrodes in the 2 DEG layer wherein the gate electrode is disposed at a first distance from the first source/drain electrode and a second distance from the second source/drain electrode and the first distance is different from the second distance.
The invention relates generally to the configurations and methods of manufacturing the semiconductor devices. More particularly, this invention relates to an asymmetrical blocking gallium nitride (GaN) switch.
2. Description of the Prior ArtConventional methods of configuring and manufacturing a gallium nitride (GaN) based field effect transistors (FETs) are still challenged with the technical issues for providing a bidirectional asymmetrical blocking capabilities to function as a bidirectional switch. It is often demanded to provide lateral GaN based asymmetrical blocking function for optimal applications in devices such as direct high voltage buck converter and dual boost bridgeless PFC.
However, the benefits of asymmetrical blocking are not achieved due to the limitations in the conventional applications of the blocking switches. Specifically, for bidirectional switch applications, the RB-IGBT devices and symmetrical bidirectional blocking GaN switches are commonly implemented. The silicon based bidirectional blocking devices are vertical devices and are intrinsically symmetrical. The GaN devices as shown in
Therefore, there is a need to provide new and improved device configuration and manufacturing methods to make bidirectional GaN blocking switches with asymmetrical blocking capabilities to resolve the above mentioned limitations and difficulties.
SUMMARY OF THE PRESENT INVENTIONIt is therefore an aspect of the present invention to provide a new and improved device configuration and manufacturing method to provide a high electron mobility transistor (HEMT) power device that provides the functions of asymmetrical bidirectional blocking switch such that the above discussed difficulties and limitations may be resolved.
Specifically, it is an aspect of the present invention to provide improved device configuration and method for manufacturing a semiconductor GaN-based HEMT power device with the functions of asymmetrical bidirectional blocking for applications to switch with asymmetrical voltage stress such that the Rds-on and the capacitive loss can be minimized thus reduce the unnecessary loss caused by symmetrical blocking switches commonly implemented in the conventional designs.
It is another aspect of the present invention to provide improved device configuration and method for manufacturing the GaN-based high electron mobility transistor (HEMT) power device with optimized lateral configuration for designing and manufacturing asymmetrical blocking switches such that commonly layout constraint that impose different parasitic inductances to cause asymmetrical blocking and asymmetrical voltage overshoots may be better considered and controlled as part of the design and manufacturing processes.
It is another aspect of the present invention to provide improved device configuration and method for manufacturing a semiconductor GaN-based HEMT power device with asymmetrical blocking capabilities with configurations by implementing either a single or dual gate configurations such that the switch functions and performances of the switching devices may be more flexible and conveniently controlled.
Briefly in a preferred embodiment this invention discloses a high electron mobility transistor (HEMT)gallium nitride (GaN) bidirectional blocking device that includes a hetero-junction structure comprising a first semiconductor layer interfacing a second semiconductor layer of two different band gaps thus generating an interface layer as a two-dimensional electron gas (2 DEG) layer. The HEMT GaN bidirectional blocking device further includes a first source/drain electrode and a second source/drain electrode disposed on two opposite sides of a gate electrode disposed on top of the hetero-junction structure for controlling a current flow between the first and second source/drain electrodes in the 2 DEG layer wherein the gate electrode is disposed at a first distance from the first source/drain electrode and a second distance from the second source/drain electrode and the first distance is different from the second distance.
These and other objects and advantages of the present invention will no doubt become obvious to those of ordinary skill in the art after having read the following detailed description of the preferred embodiment, which is illustrated in the various drawing figures.
Referring to
Referring to
In order to configure the bidirectional blocking switch as an asymmetrical block switch, the field plates of the first and the second drain/source electrodes, i.e., first field plate LSD-FP1 is formed to have different length from second field plate LSD-FP2. The distances between the gate and the electrodes, i.e., LGS1 and LGS2 may also be formed to have an asymmetric configuration as well.
Referring to
A first electrode 140-1 and a second electrode 140-2 are disposed on two opposite sides of a gate electrode 135 to control the bidirectional current flow through the hetero junction between the interface of the AlGaN and GaN layers. In order to configure the bidirectional GaN switch as an asymmetrical block switch, the distance between the first electrode 140-1 and the gate 135, i.e., LGS1/D2 is formed to be different from the distance between the second electrode 140-2 and the gate 135, i.e., LGS2/D1. Therefore, in this bi-directional GaN HEMT single gate device as shown in
Referring to
Although the present invention has been described in terms of the presently preferred embodiment, it is to be understood that such disclosure is not to be interpreted as limiting. Various alterations and modifications will no doubt become apparent to those skilled in the art after reading the above disclosure. Accordingly, it is intended that the appended claims be interpreted as covering all alterations and modifications as fall within the true spirit and scope of the invention.
Claims
1. A high electron mobility transistor (HEMT) gallium nitride (GaN) bidirectional blocking device comprising:
- a hetero junction structure comprises a first semiconductor layer interfacing a second semiconductor layer of two different band gaps thus generating an interface layer as a two-dimensional electron gas (2 DEG) layer; and
- a first source/drain electrode and a second source/drain electrode disposed on two opposite sides of a gate electrode disposed on top of said hetero junction structure for controlling a current flow between the first and second source/drain electrodes in the 2 DEG layer wherein the gate electrode is disposed at a first distance from the first source/drain electrode and a second distance from the second source/drain electrode and the first distance is different from the second distance.
2. The HEMT GaN bidirectional blocking device of claim 1 wherein:
- the gate electrode further comprises a first field plate extending toward the first source/drain electrode and a second field plate extending toward the second source/drain electrode wherein the first field plate and second field plate are configure asymmetrically.
3. The HEMT GaN bidirectional blocking device of claim 1 further comprising:
- a sapphire substrate for supporting the hetero junction structure thereon.
4. The HEMT GaN bidirectional blocking device of claim 1 wherein:
- the hetero junction structure comprises a gallium nitride (GaN) as the first semiconductor layer interfacing an AlGaN layer as the second semiconductor layer.
5. The HEMT semiconductor power device of claim 1 wherein:
- the first semiconductor layer is an N-type gallium nitride layer and the second semiconductor layer is an N-type AlGaN layer disposed on top of the gallium nitride layer.
6. The HEMT GaN bidirectional blocking device of claim 1 further comprising:
- a GaN buffer layer disposed on top of a bottom substrate for supporting the hetero junction structure thereon.
7. The HEMT GaN bidirectional blocking device of claim 1 wherein:
- the gate electrode comprises a P-type AlGaN gate.
8. The HEMT GaN bidirectional blocking device of claim 1 wherein:
- the first source/drain electrode and the second source/drain electrode are composed of a metal selected from a group of metals consists of Ti, Al, Ni and Au.
9. A high electron mobility transistor (HEMT) gallium nitride (GaN) bidirectional blocking device comprising:
- a hetero junction structure comprises a first semiconductor layer interfacing a second semiconductor layer of two different band gaps thus generating an interface layer as a two-dimensional electron gas (2 DEG) layer; and
- a first source/drain electrode and a second source/drain electrode disposed on two opposite sides of a top surface of the hetero junction structure;
- the first source/drain electrode further includes a first field plate extending laterally toward the second source/drain electrode with a first gate disposed underneath the first field plate; and
- the second source/drain electrode further includes a second field plate extending laterally toward the first source/drain electrode with a second gate disposed underneath the first field plate wherein the first field plate is configured to be asymmetrically relative to the second field plate.
10. The HEMT GaN bidirectional blocking device of claim 9 wherein:
- the first field plate has a length represented by LSD-FP1 and the second field plate has a length represented by LSD-FP2 and wherein LSD-FP1 is different from LSD-FP2.
11. The HEMT GaN bidirectional blocking device of claim 9 further comprising:
- a sapphire substrate for supporting the hetero junction structure thereon.
12. The HEMT GaN bidirectional blocking device of claim 9 wherein:
- the hetero junction structure comprises a gallium nitride (GaN) as the first semiconductor layer interfacing an AlGaN layer as the second semiconductor layer.
13. The HEMT semiconductor power device of claim 9 wherein:
- the first semiconductor layer is an N-type gallium nitride layer and the second semiconductor layer is an N-type AlGaN layer disposed on top of the gallium nitride layer.
14. The HEMT GaN bidirectional blocking device of claim 9 further comprising:
- a GaN buffer layer disposed on top of a bottom substrate for supporting the hetero junction structure thereon.
15. The HEMT GaN bidirectional blocking device of claim 1 wherein:
- the first gate and the second gate comprise a first P-type AlGaN gate and a second P-type AlGaN gate.
16. The HEMT GaN bidirectional blocking device of claim 1 wherein:
- the first source/drain electrode and the second source/drain electrode are composed of a metal selected from a group of metals consists of Ti, Al, Ni and Au.
17. A method of forming a high electron mobility transistor (HEMT) gallium nitride (GaN) bidirectional blocking device comprising:
- forming a hetero-junction structure from a first semiconductor layer interfacing a second semiconductor layer having different band gaps to make a two dimensional gas (2 DEG) at the hetero junction structure;
- forming a first source/drain electrode and second source/drain electrode on a top surface and at two opposite ends of the hetero junction structure; and
- forming a gate on the top surface of the hetero junction structure with a distance from the first source/drain electrode represented by LGS1/D2 and a distance from the second source/drain electrode represented by LGS2/D1 wherein LGS1/D2 is different from LGS2/D1.
18. The method of claim 17 wherein:
- the process of forming the gate further comprising a step of forming the gate as P-type AlGaN gate.
19. A method of forming a high electron mobility transistor (HEMT) gallium nitride (GaN) bidirectional blocking device comprising:
- forming a hetero junction structure from a first semiconductor layer interfacing a second semiconductor layer having different band gaps to make a two dimensional gas (2 DEG) at the hetero junction structure;
- forming a first source/drain electrode and second source/drain electrode on a top surface and at two opposite ends of the hetero junction structure;
- forming a first field plate extending from the first source/drain electrode toward the second source/drain electrode and forming a second field plate extending from the second source/drain electrode toward the first source/drain electrode with the second field plate configured asymmetrically from the first field plate;
- forming a first gate underneath the first field plate and forming a second gate underneath the second field plate.
20. The method of claim 17 wherein:
- the process of forming the first and the second gates further comprise a step of forming the gates as P-type AlGaN gates.
Type: Application
Filed: Aug 23, 2016
Publication Date: Mar 15, 2018
Inventor: David Sheridan (Greensboro, NC)
Application Number: 15/244,819