Optical Semiconductor Device Current Blocking Region Design
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Solution Overview
Problem
Semiconductor devices with buried hetero-structures face issues with leak current in current blocking regions, leading to increased threshold current, thermal saturation, and discontinuous light output characteristics, particularly at high output and high temperature operations.
Innovation Solution
The semiconductor device features a mesa-stripe with a double hetero-structure and current blocking regions with a narrower n-type current blocking layer distance compared to the p-type cladding layer width, optimized p-type impurity concentration, and a quantum well or strain super-lattice active layer, along with temperature control and optical coupling for efficient light output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If forward bias is applied to the pn junction between the p-type InP current blocking layer and the n-type InP cladding layer, then current injection to the active layer is improved, but leak current is generated through the pn junction
Solution Approach 1:
The patent extracts the harmful forward bias condition from the pn junction between the p-type current blocking layer and n-type cladding layer by applying reverse bias instead. This eliminates the leak current path while preserving the current blocking function, directly resolving the contradiction between current injection efficiency and leak current generation.
Solution Approach 2:
The patent changes the bias parameter from forward bias to reverse bias for the pn junction between the p-type current blocking layer and n-type cladding layer. This parameter change eliminates the leak current while maintaining the electrical isolation function, resolving the contradiction between current confinement and leak current.
2Productivity
If the current blocking region structure is used to confine current, then current constrictivity is improved, but leak current causes thermal saturation and increases threshold current
Solution Approach 1:
The patent applies different bias conditions to different regions: the pn junction between p-type current blocking layer and n-type cladding layer is reverse biased to eliminate leak current, while the pn junction between p-type contact layer and n-type cladding layer remains forward biased for current injection. This local quality differentiation resolves the contradiction between current constrictivity and threshold current increase.
Solution Approach 2:
The patent converts the potentially harmful leak current path into a beneficial current blocking mechanism by applying reverse bias to the pn junction between p-type current blocking layer and n-type cladding layer. The reverse-biased junction acts as an effective barrier, transforming what would be a leak path into a strong isolation barrier, thus resolving the contradiction between current confinement and energy loss.
3Reliability
If the pnpn-type thyristor structure is formed, then current blocking function is enhanced, but leak current activates the thyristor and causes continuous current flow
Solution Approach 1:
The patent applies preliminary anti-action by reverse biasing the pn junction between p-type current blocking layer and n-type cladding layer before operation. This preliminary reverse bias prevents the leak current from reaching the level needed to activate the thyristor structure, thus preventing continuous current flow while maintaining reliable current blocking function.
Solution Approach 2:
The patent uses the reverse-biased pn junction as a feedback mechanism to monitor and control the electrical conditions. The reverse bias condition provides continuous feedback that prevents thyristor activation by maintaining an electrical state that blocks leak current, thus ensuring reliable current blocking without continuous current flow.
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
This configuration reduces leak current, improves current constrictivity, and enables high-output, low-threshold operation with reduced thermal saturation, making it suitable for high-temperature and high-capacity optical communication systems.
Implementation Method 1
a current blocking region having pn junction and composed of one material on side surface portions of the mesa of the double hetero-structure
Implementation Method 2
a difference of refractive indices is generated between the current blocking region and the active layer in the semiconductor device having such buried current blocking region, so that the semiconductor device has a horizontal optical waveguide function for confining generated light within the active layer
Implementation Method 3
The active layer has a quantum well structure or a strain super-lattice quantum well structure
Implementation Method 4
forward bias is applied to the pn junction between the p-type InP current blocking layer 5 and the n-type InP cladding layer 2 when the semiconductor device is operative
Data Source
AI summary
A semiconductor device of the invention is formed so that n-type InP current blocking layers enter the inside of p-type InP cladding layers, i.e., the n-type current blocking layers ride over the upper part of the p-type InP cladding layers, so that a distance between the n-type InP current block layers composing a current blocking region is narrower than a width of the p-type cladding layers contacting with the n-type InP current blocking layers. Thereby, the semiconductor device whose leak current in the current blocking region may be reduced which permits high-output and high-temperature operations may be readily fabricated.