Back to results
US 8,525,229 B2Granted
Semiconductor device
AssigneeRenesas Electronics Corporation
InventorsYasuhiro Okamoto, Yuji Ando, Takashi Inoue, Tatsuo Nakayama, Hironobu Miyamoto
Life of this patent
Estimating the term…
Abstract
A semiconductor device includes a channel layer, an electron-supplying layer provided on the channel layer, a cap layer provided on the electron-supplying layer and creating lattice match with the channel layer, and ohmic electrodes provided on the cap layer. The cap layer has a composition of (InyAl1-y)zGa1-zN (0≦y≦1, 0≦z≦1). The z for such cap layer monotonically decreases as being farther away from the electron-supplying layer.
Claims46
A semiconductor device, comprising:
- a channel layer;
- an electron-supplying layer provided on said channel layer;
- a cap layer, provided on said electron-supplying layer and creating lattice match with said channel layer;
- and
- an ohmic electrode provided on said cap layer,
- wherein said cap layer has a composition of (InyAl1-y)zGa1-zN where (0≦y≦1, 0≦z≦1),
- wherein a boundary surface between said electron-supplying layer and said cap layer contains at least In, and in said cap layer a ratio of InAlN in the (InyAl1-y)zGa1-zN decreases from said boundary surface to a side of said cap layer opposite said boundary surface,
- wherein said electron-supplying layer has a composition of (InuAl1-u)xGa1-xN (0≦u≦1, 0<x≦1),
- wherein said cap layer creates lattice match with both said channel layer and said electron-supplying layer,
- wherein said semiconductor device further comprises a gate electrode coupled to said electron-supplying layer, said gate electrode constituting a hetero junction field effect transistor, and
- wherein said ohmic electrode functions as a source electrode or a drain electrode of said hetero junction field effect transistor.
8 more elements
A semiconductor device, comprising:
- a channel layer;
- an electron-supplying layer provided on said channel layer;
- a cap layer, provided on said electron-supplying layer and creating lattice match with said channel layer;
- and
- an ohmic electrode provided on said cap layer,
- wherein said cap layer has a composition of (InyAl1-y)zGa1-zN where (0≦y≦1, 0≦z≦1),
- wherein a boundary surface between said electron-supplying layer and said cap layer contains at least In, and in said cap layer a ratio of InAlN in the (InyAl1-y)zGa1-zN decreases from said boundary surface to a side of said cap layer opposite said boundary surface,
- wherein said electron-supplying layer has a composition of (InuAl1-u)xGa1-xN (0≦u≦1, 0<x≦1),
- wherein said cap layer creates lattice match with both said channel layer and said electron-supplying layer, and
- wherein said cap layer is doped with n-type dopant, which is capable of creating negative charge that is not lower than a spontaneous polarized charge.
7 more elements
A semiconductor device, comprising:
- a channel layer;
- an electron-supplying layer provided on said channel layer;
- a cap layer, provided on said electron-supplying layer and creating lattice match with said channel layer;
- and
- an ohmic electrode provided on said cap layer,
- wherein said cap layer has a composition of (InyAl1-y)zGa1-zN where (0≦y≦1, 0≦z≦1),
- wherein a boundary surface between said electron-supplying layer and said cap layer contains at least In, and in said cap layer a ratio of InAlN in the (InyAl1-y)zGa1-zN decreases from said boundary surface to a side of said cap layer opposite said boundary surface,
- wherein said electron-supplying layer has a composition of (InuAl1-u)xGa1-xN (0≦u≦1, 0<x≦1),
- wherein said cap layer creates lattice match with both said channel layer and said electron-supplying layer, and
- wherein z in said cap layer is selected so that a valence band discontinuity is equal to or lower than an energy level represented by (kTch/q), where k is Boltzmann constant, Tch is 200° C., and q is elementary charge at an interface with said electro-supplying layer.
7 more elements
Dependencies are inferred from the claim text.