Semiconductor Device Leakage Current Suppression via Intermediate Layer
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Solution Overview
Problem
In high-speed semiconductor devices, such as heterostructure bipolar transistors and photodiodes, it is challenging to suppress leakage currents due to device size limitations and series resistance, particularly when using InGaAs with a small bandgap, which affects the miniaturization and reliability of these devices.
Innovation Solution
A semiconductor device structure is implemented with a non-doped semiconductor layer covering the upper surface of an intermediate mesa, creating a potential difference that reduces voltage on the side surface, allowing for a smaller device size and lower series resistance, thereby suppressing leakage currents. This is achieved by strategically placing semiconductor layers with different bandgaps and impurity concentrations to manage the electric field and potential distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the device is miniaturized for high-speed operation, then the operation speed is improved, but leakage current increases due to surface effects
Solution Approach 1:
A non-doped InGaAsP intermediate layer is introduced between the InGaAs collector layer and the InP emitter layer. This intermediate layer acts as a mediator to reduce the electric field concentration at the mesa side surface, thereby suppressing leakage current while maintaining the miniaturized device structure for high-speed operation.
Solution Approach 2:
The invention changes the doping parameter by introducing a non-doped (intrinsic) intermediate layer with different material composition (InGaAsP) between the doped layers. This parameter change creates a potential barrier that reduces the electric field at the surface, suppressing leakage current without compromising the high-speed performance enabled by device miniaturization.
2Reliability
If a non-doped InGaAsP intermediate layer is added to suppress leakage current, then reliability is improved, but device complexity increases
Solution Approach 1:
The collector region is segmented into multiple layers: a doped InGaAs collector layer adjacent to the base layer, and a non-doped InGaAsP intermediate layer between the collector and emitter. This segmentation allows each layer to perform its specific function - the doped layer for charge transport and the non-doped layer for electric field management - thereby suppressing leakage current while maintaining structural clarity.
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 effectively reduces device size, lowers series resistance, and minimizes leakage currents, enabling high-speed operation and dense array disposition of semiconductor devices while maintaining device reliability.
Implementation Method 1
creating a potential difference that reduces voltage on the side surface
Data Source
Figure 1(A)~1(B)
Figure 2(A)~2(B)
Figure 3(A)~3(B)
AI summary
This invention provides a semiconductor device which can reduce a device size, reduce a series resistance, and suppress a leakage current. In this invention, a layer in which the potential level difference normally unrequired for device operation is generated is positively inserted in a device structure. The potential level difference has such a function that even if a semiconductor having a small bandgap is exposed on a mesa side surface, a potential drop amount of the portion is suppressed, and a leakage current inconvenient for device operation can be reduced. This effect can be commonly obtained for a heterostructure bipolar transistor, a photodiode, an electroabsorption modulator, and so on. In the photodiode, since the leakage current is alleviated, the device size can be reduced, so that in addition to improvement of operating speed with a reduction in series resistance, it is advantageous that the device can be densely disposed in an array.