Semiconductor device, semiconductor laser, and high electron mobility transistor
First Claim
Patent Images
1. A semiconductor device including:
- a semiconductor substrate having a surface; and
a strained superlattice structure comprising a plurality of first semiconductor layers having a first strain in a direction with respect to the semiconductor substrate and a plurality of second semiconductor layers having a second strain in the same direction as and different in magnitude from the first strain, the first semiconductor layers and the second semiconductor layers being alternatingly laminated and a difference between the second strain and the first strain gradually decreases in absolute value from a second semiconductor layer toward an adjacent first semiconductor layer.
1 Assignment
0 Petitions
Accused Products
Abstract
A semiconductor device includes a semiconductor substrate having a surface; and a strained superlattice structure including first semiconductor layers having a first strain in a direction with respect to the semiconductor substrate and second semiconductor layers having a second strain in the same direction as and different in magnitude from the first strain, the first semiconductor layers and the second semiconductor layers being alternatingly laminated. The difference in strains between the first semiconductor layers and the second semiconductor layers is reduced, so that the crystalline quality of the strained superlattice structure is improved.
-
Citations
11 Claims
-
1. A semiconductor device including:
-
a semiconductor substrate having a surface; and a strained superlattice structure comprising a plurality of first semiconductor layers having a first strain in a direction with respect to the semiconductor substrate and a plurality of second semiconductor layers having a second strain in the same direction as and different in magnitude from the first strain, the first semiconductor layers and the second semiconductor layers being alternatingly laminated and a difference between the second strain and the first strain gradually decreases in absolute value from a second semiconductor layer toward an adjacent first semiconductor layer.
-
-
2. A semiconductor device including:
-
a semiconductor substrate having a surface; a strained superlattice structure comprising a plurality of first semiconductor layers having a first strain in a direction with respect to the semiconductor substrate and a plurality of second semiconductor layers having a second strain in the same direction as and different in magnitude from the first strain, the first semiconductor layers and the second semiconductor layers being alternatingly laminated; and a third semiconductor layer in the vicinity of the strained superlattice structure, the third semiconductor layer being parallel to the surface of the substrate and having a third strain opposite in direction from the first strain.
-
-
3. A semiconductor laser comprising:
-
a semiconductor substrate of a first conductivity type and having opposed front and rear surfaces; a first cladding layer of the first conductivity type disposed on the front surface of the semiconductor substrate, the first cladding layer having no strain with respect to the semiconductor substrate and having a band gap energy; an active layer comprising a pair of separate confinement heterostructure layers disposed on the first cladding layer and a strained superlattice structure interposed between the separate confinement heterostructure layers, the separate confinement heterostructure layers comprising a material having a band gap energy smaller than the band gap energy of the first cladding layer, the strained superlattice structure comprising a plurality of well layers having a first strain in a direction with respect to the semiconductor substrate and a plurality of barrier layers interposed between the well layers and having a second strain in the same direction as and smaller than the first strain; a second cladding layer of a second conductivity type, opposite the first conductivity type, disposed on the active layer and comprising the same material as the first cladding layer; a contact layer of the second conductivity type disposed on the second cladding layer and having no strain with respect to the substrate; a first electrode disposed on the substrate; and a second electrode disposed on the contact layer. - View Dependent Claims (4, 5, 6, 7)
-
-
8. A high electron mobility transistor comprising:
-
a semi-insulating substrate having a surface; an undoped electron transit layer disposed on the surface of the semi-insulating substrate; an undoped pseudo electron transit layer disposed on the electron transit layer and having a first strain in a direction with respect to the substrate; an electron supply layer disposed on the pseudo electron transit layer and having a high concentration of a dopant impurity producing n type conductivity; a gate electrode disposed on a portion of the electron supply layer, making a Schottky contact with the electron supply layer; a source electrode and a drain electrode disposed on portions of the electron supply layer at opposite sides of and spaced apart from the gate electrode, making ohmic contacts with the electron supply layer; and an n type crystalline defect preventing layer interposed between the pseudo electron transit layer and the electron supply layer and having a second strain in the same direction as and smaller than the first strain. - View Dependent Claims (9, 11)
-
-
10. A high electron mobility transistor comprising:
-
a semi-insulating substrate having a surface; a undoped electron transit layer disposed on the surface of the semi-insulating substrate; an undoped pseudo electron transit layer disposed on the electron transit layer and having a first strain in a direction with respect to the substrate; an electron supply layer disposed on the pseudo electron transit layer and having a high concentration of a dopant impurity producing n type conductivity; a gate electrode disposed on a portion of the electron supply layer, making a Schotty contact with the electron layer; a source electrode and a drain electrode disposed on portions of the electron supply layer at opposite sides of and spaced apart from the gate electrode, making ohmic contacts with the electron supply layer; and an undoped crystalline defect preventing layer interposed between the pseudo electron transit layer and the electron transit layer and having a second strain in the same direction as and smaller than the first strain.
-
Specification