Scalable Voltage Source Monolithic Stack
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Solution Overview
Problem
Existing scalable voltage sources, particularly those using III-V materials, face limitations in achieving high voltage values and efficient area utilization, with prior art struggling to produce voltages above 3 volts effectively and requiring larger illumination areas.
Innovation Solution
A scalable voltage source is developed by connecting multiple semiconductor diodes with p-n junctions in series, incorporating tunnel diodes with higher bandgap semiconductor layers and monolithic integration, allowing for a stacked structure that achieves source voltages greater than 3 volts with reduced illumination area requirements and improved scalability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If multiple partial voltage sources are connected in series to achieve higher voltages, then the source voltage increases above 3 volts, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent merges multiple partial voltage sources into a single monolithic stack structure where N semiconductor diodes and tunnel diodes are integrated in series. This combining approach achieves high voltages (above 3V, preferably above 4V) while reducing the number of separate components and interconnections needed, thereby managing device complexity despite the high voltage requirement.
Solution Approach 2:
The patent transitions from lateral arrangement of voltage sources to a vertical stacked configuration. By stacking the semiconductor diodes and tunnel diodes in the vertical dimension, the patent achieves high source voltages through series connection while minimizing the lateral illumination area, effectively using the third dimension to resolve the complexity-voltage trade-off.
2Area of stationary object
If the illumination area is reduced to save space, then area savings are achieved, but the manufacturing precision requirements increase to maintain voltage uniformity
Solution Approach 1:
The patent applies local quality by creating non-uniform absorption layer thicknesses within the stack. The total thickness of p and n absorption layers increases from the topmost diode to the bottommost diode, with each diode having optimized local thickness to compensate for voltage deviations. This local optimization ensures that all diodes contribute equally to the total voltage despite the compact vertical stacking, maintaining voltage uniformity while minimizing the lateral illumination area.
3Stability of the object's composition
If tunnel diodes with higher band gap materials are introduced to improve voltage characteristics, then the source voltage stability improves, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent introduces tunnel diodes as intermediary elements between the semiconductor diodes in the stack. These tunnel diodes, made from higher band gap semiconductor materials with modified stoichiometry, serve as voltage-stabilizing components that enable the achievement of stable high voltages (above 3V) while being monolithically integrated into the stack, thereby managing the complexity through functional integration rather than separate components.
4Use of energy by moving object
If the absorption layer thickness is increased to improve light absorption, then the energy conversion efficiency improves, but the total stack thickness increases beyond acceptable limits
Solution Approach 1:
The patent optimizes the absorption layer thickness parameters by creating a gradient structure where the total thickness of p and n absorption layers increases from top to bottom within the stack. This parameter optimization ensures sufficient light absorption and energy conversion efficiency while maintaining the total stack thickness below 12 μm, achieving the right balance between energy efficiency and compactness through controlled thickness variation.
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 approach enables the production of voltage sources above 4 volts with a cost-effective and reliable monolithic structure, offering significant area savings and improved usability as a reference voltage source, with partial source voltage deviations minimized to enhance scalability.
Implementation Method 1
a tunnel diode is formed between each pair of successive partial voltage sources wherein the tunnel diode has several semiconductor layers with a higher band gap than the band gap of the p/n absorption layers
Implementation Method 2
a scalable voltage source is provided comprising a number N of partial voltage sources connected in series and designed as semiconductor diodes, wherein each of the partial voltage sources has a semiconductor diode with a pn junction
Implementation Method 3
the p-absorption layer is passivated by a p-doped passivation layer with a larger band gap than the band gap of the p-absorption layer, and the semiconductor diode has an n-absorption layer, wherein the n-absorption layer is passivated by an n-doped passivation layer with a larger band gap than the band gap of the n-absorption layer
Data Source
Figure 1~2
Figure 3~4
AI summary
A scalable voltage source comprising a number N of partial voltage sources connected in series, each of which is a semiconductor diode having a pn junction, and each semiconductor diode having a p-doped absorption layer, wherein the p-absorption layer is passivated by a p-doped passivation layer with a band gap larger than the band gap of the p-absorption layer, and the semiconductor diode having an n-absorption layer, wherein the n-absorption layer is passivated by an n-doped passivation layer with a band gap larger than the band gap of the n-absorption layer, and the partial voltages of the individual partial voltage sources have a deviation of less than 20% from each other, and a tunnel diode is formed between each pair of successive partial voltage sources.wherein the tunnel diode has several semiconductor layers with a higher band gap than the band gap of the p/n absorption layers, and the semiconductor layers with the higher band gap each consist of a material with a modified stoichiometry and/or elemental composition than the p/n absorption layers of the semiconductor diode, and the partial voltage sources and the tunnel diodes are monolithically integrated together, and together form a first stack with a top and a bottom, and the number N of partial voltage sources is greater than or equal to three, and the light strikes the stack at the top, and the size of the illumination area at the top of the stack is essentially the size of the area of the stack at the top, and the first stack has a total thickness of less than 12 µm, and at 300 K the first stack has a source voltage greater than 3 volts,provided that the first stack is irradiated with a photon stream of a specific wavelength, and wherein, in the direction of incidence of the light, the total thickness of the p and n absorption layers of a semiconductor diode increases from the top diode to the bottom diode.