Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
152 words
A semiconductor device which comprises an undoped GaAs layer (21), an intermediate undoped layer (24) and an undoped G a 1-x Al x As layer (3) stacked on a substrate (1) in this order, in which said intermediate undoped layer (24) is an undoped In y Ga 1 -y As layer, or an undoped GaAs -z sb z layer, or a superlattice layer formed by alternately stacking at least one undoped In y Ga 1-y As layer and at least one undcped GaAs 1-z Sb z layer, or a superlattice layer formed by alternately stacking at least one undoped In y Ga 1-y As layer and at least one undoped GaAs layer, or a superlattice layer formed by alternately stacking at least one undoped GaAs 1-z Sb z and at least one undcped GaAs layer, wherein 1 ≧ x > 0, 1 ≧ y > 0, and 1 ≧ z > 0.
Claim 2
Dependent Claim
152 words
A semiconductor device which comprises an undoped GaAs layer (21), an intermediate undoped layer (24) and an undoped G a 1-x Al x As layer (3) stacked on a substrate (1) in this order, in which said intermediate undoped layer (24) is an undoped In y Ga 1 -y As layer, or an undoped GaAs -z sb z layer, or a superlattice layer formed by alternately stacking at least one undoped In y Ga 1-y As layer and at least one undcped GaAs 1-z Sb z layer, or a superlattice layer formed by alternately stacking at least one undoped In y Ga 1-y As layer and at least one undoped GaAs layer, or a superlattice layer formed by alternately stacking at least one undoped GaAs 1-z Sb z and at least one undcped GaAs layer, wherein 1 ≧ x > 0, 1 ≧ y > 0, and 1 ≧ z > 0.
Claim 3
Dependent Claim
15 words
The semiconductor device of claim 1, wherein said substrate (1) is a semiinsulating GaAs crystal.
Claim 4
Dependent Claim
28 words
The semiconductor device of claim 1 or 2, wherein the value of x is 0.1 to 0.5, and the value of y and z are 0.05 to 0.5.
Claim 5
Dependent Claim
40 words
The semiconauctor device of any of claims 1 to 3, wherein said intermediate undoped layer (24) is an undoped In y Ga 1-y As layer or an undoped GaAs 1-z Sb z layer, and is 5 to 50 nm thick.
Claim 6
Dependent Claim
18 words
The semiconductor device of claim 4, wherein said intermediate undoped layer (24) is 10 to 20 nm thick.
Claim 7
Dependent Claim
29 words
The semiconductor device of any of claims 1 to 3, wherein said intermediate undoped layer (24) is one of said superlattice layers, and is 5 to 100 nm thick.
Claim 8
Dependent Claim
72 words
The semiconductor device of any of claims 1 to 6, including an n-type Ga 1-x Al x As layer (4) provided on said undoped Ga 1-x Al x As layer (3), a drain region (10) and a source region (9) which reach said undoped GaAs layer (21) located on said substrate (1), and a drain electrode (8), a source electrode (6) and a gate electrode (7), thereby constructing a field effect transistor.