GaSb Light Receiving Device with Co-Doped Substrate
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Solution Overview
Problem
GaSb substrates used in light receiving devices have a high absorption coefficient for infrared light, leading to reduced sensitivity due to optical absorption, which attenuates the intensity of incident light passing through the substrate.
Innovation Solution
A light receiving device with a GaSb substrate co-doped with p-type and n-type dopants, featuring a stacked semiconductor layer with a super-lattice structure on the principal surface and an incident surface on the back surface, reduces optical absorption by carrier compensation, allowing infrared light to transmit through the substrate and be absorbed in the optical absorption layer, generating photocurrent.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a GaSb substrate is used for growing semiconductors, then semiconductor growth is enabled, but the substrate absorbs infrared light strongly, reducing light transmittance and device sensitivity
Solution Approach 1:
The patent changes the electrical parameters of the GaSb substrate by co-doping it with both p-type (e.g., Zn) and n-type (e.g., Te) dopants. This parameter change reduces the carrier concentration in the substrate, thereby reducing free carrier absorption of infrared light and improving light transmittance while maintaining the substrate's utility for semiconductor growth
Solution Approach 2:
The patent creates a composite doped structure in the GaSb substrate by combining multiple dopant elements (p-type and n-type) within the same substrate material. This composite doping approach allows simultaneous achievement of reduced optical absorption and maintained crystalline quality for device fabrication
2Strength
If the substrate thickness is increased to support device structure, then mechanical strength is improved, but optical absorption increases, reducing sensitivity
Solution Approach 1:
By changing the electrical parameters through co-doping, the substrate maintains low optical absorption even at greater thicknesses. The reduced carrier concentration from co-doping allows the substrate to be thicker for mechanical support without proportionally increasing optical absorption, thus preserving sensitivity
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution enhances light transmittance and sensitivity for infrared wavelengths by reducing the optical absorption coefficient, enabling efficient photocurrent generation and output in the light receiving device.
Implementation Method 1
The optical absorption layer includes a super-lattice structure including a first semiconductor layer and a second semiconductor layer that are alternately stacked... receives an incident light... generating photocurrent
Implementation Method 2
the substrate containing GaSb semiconductor co-doped with a p-type dopant and an n-type dopant... reduces optical absorption by carrier compensation
Data Source
AI summary
A light receiving device includes a substrate having a principal surface and a back surface, the substrate containing GaSb semiconductor co-doped with a p-type dopant and an n-type dopant; a stacked semiconductor layer disposed on the principal surface of the substrate, the stacked semiconductor layer including an optical absorption layer; and an incident surface provided on the back surface of the substrate that receives an incident light. The optical absorption layer includes a super-lattice structure including a first semiconductor layer and a second semiconductor layer that are alternately stacked. In addition, the first semiconductor layer contains gallium and antimony as constituent elements. The second semiconductor layer is composed of a material different from a material of the first semiconductor layer.