US 12,446,250 B2
Normally-off mode polarization super junction GaN-based field effect transistor and electrical equipment
Hiroji Kawai, Oyama (JP); Shuichi Yagi, Oyama (JP); and Hironobu Narui, Oyama (JP)
Assigned to POWDEC K.K., Oyama (JP)
Appl. No. 17/921,225
Filed by POWDEC K.K., Oyama (JP)
PCT Filed Sep. 16, 2021, PCT No. PCT/JP2021/034029
§ 371(c)(1), (2) Date Oct. 25, 2022,
PCT Pub. No. WO2022/190414, PCT Pub. Date Sep. 15, 2022.
Claims priority of application No. 2021-038916 (JP), filed on Mar. 11, 2021; and application No. 2021-143739 (JP), filed on Sep. 3, 2021.
Prior Publication US 2023/0170407 A1, Jun. 1, 2023
Int. Cl. H10D 30/47 (2025.01); H10D 8/00 (2025.01); H10D 30/01 (2025.01); H10D 62/10 (2025.01); H10D 62/824 (2025.01); H10D 62/85 (2025.01); H10D 64/27 (2025.01)
CPC H10D 30/4732 (2025.01) [H10D 8/422 (2025.01); H10D 30/015 (2025.01); H10D 62/124 (2025.01); H10D 64/411 (2025.01); H10D 64/512 (2025.01); H10D 62/824 (2025.01); H10D 62/8503 (2025.01)] 9 Claims
OG exemplary drawing
 
1. A normally-off mode polarization super junction GaN-based field effect transistor, comprising:
a first undoped GaN layer,
an AlxGa1-xN layer (0<x<1) on the first undoped GaN layer,
a second undoped GaN layer having an island-like shape on the AlxGa1-xN layer,
a p-type GaN layer on the second undoped GaN layer,
a p-type InyGa1-yN layer (0<y<1) on the p-type GaN layer,
a source electrode on the AlxGa1-xN layer,
a drain electrode on the AlxGa1-xN layer,
a first gate electrode electrically connected to the p-type InyGa1-yN layer; and
a p-type InzGa1-zN layer (0<z<1) and a second gate electrode thereon on the AlxGa1-xN layer which are located beside one end of the second undoped GaN layer on the side of the source electrode,
the AlxGa1-xN layer having a protrusion having an island-like shape as the same as the second undoped GaN layer on an upper part just below the second undoped GaN layer, the p-type InzGa1-zN layer and the second gate electrode being provided on a flat upper surface of a part of the AlxGa1-xN layer which is located beside the protrusion,
the first gate electrode and the second gate electrode being provided independently each other,
the p-type GaN layer existing on the whole surface of the second undoped GaN layer or on only one side of the surface of the second undoped GaN layer on the side of the source electrode,
the p-type InyGa1-yN layer existing on only one side of the surface of the p-type GaN layer on the side of the source electrode if the p-type GaN layer exists on the whole surface of the second undoped GaN layer or existing on the whole surface or a part of the surface of the p-type GaN layer if the p-type GaN layer exists on only one side of the surface of the second undoped GaN layer on the side of the source electrode,
n0≤n1<n2<n3 and n0<( 1/1000)×n3
being satisfied at a non-operating time if the concentration of a two-dimensional electron gas formed in the first undoped GaN layer in the vicinity part of a hetero-interface between the first undoped GaN layer and the AlxGa1-xN layer just below the second gate electrode is denoted as n0, the concentration of the two-dimensional electron gas just below the first gate electrode is denoted as n1, the concentration of the two-dimensional electron gas in a polarization super junction region is denoted as n2 and the concentration of the two-dimensional electron gas in a part between the polarization super junction region and the drain electrode is denoted as n3,
p1>p2
being satisfied if the concentration of a two-dimensional hole gas formed in the second undoped GaN layer in the vicinity part of a hetero-interface between the second undoped GaN layer and the AlxGa1-xN layer just below the first gate electrode is denoted as p1 and the concentration of the two-dimensional hole gas in the polarization super junction region is denoted as p2.