High-Resistance Silicon Substrate for Microwave Devices
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Solution Overview
Problem
Microwave devices on traditional silicon substrates experience high transmission loss due to the diffusion of atoms from compound layers into high-resistance silicon substrates, forming p-type semiconductor regions that impair device efficiency, and accurate compensation doping is hindered by fluctuating impurity concentrations.
Innovation Solution
A semiconductor structure and manufacturing method involving a high-resistance silicon substrate with locally formed n-type semiconductor regions and a III-V group compound layer that diffuses into the substrate to form p-type regions, creating a depleted space charge region and reducing parasitic capacitance, thereby improving resistivity and radio frequency characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a compound layer is epitaxially grown on a high-resistance silicon substrate, then the device structure is formed, but atoms in the compound layer diffuse into the substrate forming p-type semiconductor regions that increase transmission loss
Solution Approach 1:
The patent applies preliminary anti-action by introducing n-type impurities into the high-resistance silicon substrate before the compound layer is epitaxially grown. This pre-established n-type doping creates a compensation effect that counteracts the harmful p-type diffusion that will occur during subsequent epitaxial growth, thereby preventing the formation of high-loss regions while allowing the device structure to be formed.
Solution Approach 2:
The patent implements preliminary action by performing n-type impurity introduction and annealing processes before the epitaxial growth of the compound layer. This preliminary doping establishes a controlled impurity distribution in advance, ensuring that when the compound layer is later grown and atoms diffuse into the substrate, the harmful effects are compensated by the pre-existing n-type regions, thus maintaining low transmission loss.
2Reliability
If n-type impurities are imported for compensation doping on the surface of the high-resistance silicon substrate, then p-type regions are compensated, but impurity concentration fluctuates making accurate doping impossible
Solution Approach 1:
The patent applies parameter changes by systematically optimizing multiple doping parameters including impurity concentration, doping depth, and annealing temperature and time. By carefully adjusting these parameters, the patent achieves stable and controllable n-type impurity distribution that compensates for p-type regions while maintaining precise control over the final impurity concentration, thus resolving the fluctuation issue.
Solution Approach 2:
The patent implements feedback control through a multi-step process involving initial doping, annealing, and characterization. The annealing process allows impurities to redistribute and stabilize, and the iterative optimization of doping parameters based on measured results enables precise control over the final impurity concentration, ensuring accurate compensation doping despite initial fluctuations.
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 method enhances the resistivity of high-resistance silicon substrates under high temperature conditions and improves the efficiency and radio frequency characteristics of microwave devices by eliminating parasitic capacitance and ensuring precise control over doping concentrations.
Implementation Method 1
atoms such as Al, Ga and the like in the compound layer will diffuse into the high-resistance silicon substrate due to a diffusion effect
Implementation Method 2
The method for forming an upper part of the high-resistance silicon substrate into a plurality of n-type semiconductor regions includes local n-type ion implantation
Implementation Method 3
The method for forming an upper part of the high-resistance silicon substrate into a plurality of n-type semiconductor regions includes local n-type ion diffusion
Implementation Method 4
the p-type semiconductor regions and the n-type semiconductor regions form a PN junction, and the p-type semiconductor regions are completely depleted to form a space charge region
Implementation Method 5
growing epitaxially a compound layer on the high-resistance silicon substrate
Data Source
AI summary
A semiconductor structure and a manufacturing method thereof is provided. The semiconductor structure includes a high-resistance silicon substrate and a compound layer located on the high-resistance silicon substrate, by performing a way such as local n-type ion implantation, local n-type ion diffusion, selective region epitaxy growth and the like to the high-resistance silicon substrate, an upper part of the high-resistance silicon substrate is formed into a plurality of local n-type semiconductor regions, p-type semiconductor conductive regions formed in the upper part of the high-resistance silicon substrate due to a diffusion of Al, Ga atoms in the compound layer are eliminated, thereby parasitic capacitance caused by a conductive substrate is greatly reduced, and a resistivity of the high-resistance silicon substrate may be improved under high temperature conditions, and then efficiencies and radio frequency characteristics of a microwave device constituted by the entire semiconductor structure are improved.