Semiconductor device and method of manufacture of the semiconductor device
OwnerKeiichi Yabusaki, Michio Ohkuboinventors
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Abstract
The semiconductor laser device has a lower clad layer, an active layer, an upper clad layer, a forward mesa forming layer, a contact layer and an insulating film, sequentially formed on the semiconductor substrate. The upper clad layer, the forward mesa forming layer, the contact layer and the insulating film form a ridge. The etching speed of the forward mesa forming layer is higher than that of the upper clad layer and lower than that of the contact layer. Because of such etching speeds, the ridge having a forward mesa structure is formed.
Claims49
A semiconductor device having a multiple layered ridge, said ridge including:
- a first semiconductor layer forming the bottom part of said ridge, said first semiconductor layer having a first etching speed in a first etchant;
- a second semiconductor layer disposed above said first semiconductor layer, said second semiconductor layer having a second etching speed in the first etchant;
- and
- a third semiconductor layer disposed above said second semiconductor layer and forming the top part of said ridge, said third semiconductor layer having a third etching speed in the first etchant, wherein the second etching speed is higher than the first etching speed and slower than the third etching speed.
A method of manufacturing a semiconductor device having a multiple layered ridge, the method comprising the steps of:
- forming a first semiconductor layer as a bottom part of the ridge, said first semiconductor layer being etched at a first etching speed by a first etchant;
- forming a second semiconductor layer above said first semiconductor layer, said second semiconductor layer being etched at a second etching speed by the first etchant;
- and
- forming a third semiconductor layer above said second semiconductor layer as a top part of the ridge, said third semiconductor layer being etched at a third etching speed by the first etchant,
- wherein the second etching speed is higher than the first etching speed and slower than the third etching speed.
A semiconductor device having a multiple layered ridge formed at a first surface of a substrate, said ridge including:
- a base attached to the substrate, an upper face located above the base, and at least a first side face located between the ridge's upper face and the base;
- a first semiconductor layer located closer to the base than the upper face of the ridge, said first semiconductor layer having a composition of Alx1Ga1−x2As where the stoichiometric parameter x1 is substantially constant;
- a second semiconductor layer located above said first semiconductor layer and below said upper face, said second semiconductor layer having a composition of Alx2Ga1−x2As where the stoichiometric parameter x2 is variable with a range of values which are less than or equal to X1;
- and
- a third semiconductor layer located above said second semiconductor layer and below said upper face, said third semiconductor layer having a composition of Alx3Ga1−x3As where the stoichiometric parameter x3 is substantially constant and substantially less than or equal to the lowest value of the stoichiometric parameter x2;
- and
- wherein said second semiconductor layer has a bottom surface located near the first semiconductor layer and top surface located near the third semiconductor layer,
- wherein the stoichiometric parameter X2 decreases monotonically from the bottom surface of the second semiconductor layer to the top surface of the second semiconductor layer, and wherein said first side face comprises a forward mesa surface.
A method of manufacturing a semiconductor device having a multiple layered ridge, the ridge having a base attached to a substrate, an upper face located above the base, and at least a first side face located between the ridge's upper face and the base, the method comprising the steps of:
- (a) forming a first semiconductor layer located closer to the base than the upper face of the ridge, the first semiconductor layer having a composition of Alx1Ga1−x1As where the stoichiometric parameter x1 is substantially constant;
- (b) forming a second semiconductor layer over the first semiconductor layer and located below the upper face, the second semiconductor layer having a bottom surface adjacent to the first semiconductor layer and top surface opposite to the bottom surface, the second semiconductor layer having a composition of Alx2Ga1−2As where the stoichiometric parameter x2 is variable with a range of values which are less than or equal to x1 , the second layer being formed such that the stoichiometric parameter x2 decreases substantially monotonically from the bottom surface of the second semiconductor layer to the top surface of the second semiconductor layer;
- and
- (c) forming a third semiconductor layer over the second semiconductor layer and located below the upper face, the third semiconductor layer having a composition of Alx1Ga1−3As where the stoichiometric parameter x3 is substantially constant and substantially less than or equal to the lowest value of the stoichiometric parameter x2 ;
- and
- (d) exposing selected portions of the first, second, and third semiconductor layers to a common etchant to form the ridge such that at least a portion of the first side surface of the ridge has a slope of a forward mesa ridge.
Dependencies are inferred from the claim text.