Mesa photodiode and method for manufacturing the same
AssigneeNEC Electronics Corporation
InventorsIsao Watanabe, Tomoaki Koi
Life of this patent
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Abstract
A mesa photodiode which includes a mesa, the sidewall of the mesa is a surface that is inclined in the direction in which the bottom of the mesa becomes wider. At least the sidewall of the mesa is covered with a semiconductor layer of a first conductivity type, a second conductivity type, a semi-insulating type, or an undoped type. The semiconductor layer is grown on at least the sidewall of the mesa. The inclined angle of the inclined surface of the mesa at the upper end portion is smaller than the inclined angle of the inclined surface of the mesa at the lower end portion.
Claims10
A mesa photodiode comprising
- a stack structure that is formed on a semiconductor substrate, said stack structure being formed by stacking and growing a buffer layer made of a semiconductor of a first conductivity type, an etching stopper layer made of a semiconductor of the first conductivity type, a second conductivity type, or an undoped type, a light-absorbing layer made of a semiconductor of the first conductivity type, the second conductivity type, or the undoped conductivity type, and a double-layer semiconductor layer of the second conductivity type in this order,
- said double-layer semiconductor layer of the second conductivity type and said light-absorbing layer forming a mesa,
- a sidewall of said mesa being an inclined surface that is inclined in a direction in which a bottom of said mesa becomes wider,
- at least said sidewall of said mesa being covered with a semiconductor layer that is grown on said sidewall, said semiconductor layer being of the first conductivity type, the second conductivity type, a semi-insulating type, or the undoped type,
- an inclined angle of said inclined surface of said mesa at an upper end portion being smaller than an inclined angle of said inclined surface of said mesa at a lower end portion.
A method for manufacturing a mesa photodiode, comprising:
- forming a stack structure on a semiconductor substrate by stacking and growing a buffer layer made of a semiconductor of a first conductivity type, an etching stopper layer made of a semiconductor of the first conductivity type, a second conductivity type, or an undoped type, a light-absorbing layer made of a semiconductor of the first conductivity type, the second conductivity type, or the undoped conductivity type, and a double-layer semiconductor layer of the second conductivity type in this order;
- processing said double-layer semiconductor layer of the second conductivity type and said light-absorbing layer into a mesa;
- and
- covering at least a sidewall of said mesa with a semiconductor layer that is grown on at least said sidewall, said semiconductor layer being of the first conductivity type, the second conductivity type, a semi-insulating type, or the undoped type;
- and
- said processing the double-layer semiconductor layer and the light-absorbing layer including forming the sidewall of said mesa on an inclined surface that is inclined in a direction in which a bottom of said mesa becomes wider, and controlling an inclined angle of said inclined surface of said mesa at an upper end portion to be smaller than an inclined angle of said inclined surface of said mesa at a lower end portion.
Dependencies are inferred from the claim text.