Asymmetrical blocking bidirectional gallium nitride switch

Abstract

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.

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 L SD-FP1  and the second field plate has a length represented by L SD-FP2  and wherein L SD-FP1  is different from L SD-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 L GS1/D2  and a distance from the second source/drain electrode represented by L GS2/D1  wherein L GS1/D2  is different from L GS2/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.