Diode String Voltage Adapter Leakage Suppression
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Solution Overview
Problem
Existing diode strings used in integrated circuits face challenges in providing a reliable high-voltage adapter due to increased leakage current and parasitic transistor activation at higher supply voltages, especially with advanced processes and smaller scales.
Innovation Solution
A diode string voltage adapter is designed with a substrate of a first conductive type, featuring diodes with deep and second well regions that are electrically floating, and heavily doped regions to minimize leakage current, where diodes are serially coupled to achieve a controlled voltage drop, with the deep and second well regions not requiring connection to a voltage, thus preventing parasitic transistor activation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If diode string is used for voltage adaptation in high supply voltage circuits, then voltage drop function is achieved, but leakage current increases and parasitic transistor activation occurs
Solution Approach 1:
The diode structure is segmented into multiple regions including a first doped region, a second doped region, a third doped region, and a fourth doped region with different conductivity types and doping concentrations. This segmentation allows each region to perform specific functions in suppressing leakage current and preventing parasitic transistor activation while maintaining the voltage drop function.
Solution Approach 2:
Different regions of the diode string are assigned different local qualities through varying doping concentrations and conductivity types. The first doped region has high doping concentration for low resistance contact, the second doped region has optimized doping for forward voltage drop, the third doped region suppresses parasitic transistors, and the fourth doped region provides additional leakage suppression. This local quality differentiation resolves the contradiction by optimizing each region for its specific function.
2Productivity
If advanced semiconductor processes with smaller scales are used, then integration density is improved, but leakage current and parasitic transistor effects worsen
Solution Approach 1:
The invention changes multiple parameters including doping concentrations, region dimensions, and conductivity type distributions to suppress parasitic transistor effects in scaled devices. By optimizing the doping concentrations in each region and adjusting the geometric parameters of the diode string, the patent achieves reliable voltage adaptation in advanced process nodes while maintaining high integration density.
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 leakage current and maintains a stable voltage drop across the diode string, enabling operation in high-voltage circuits with reduced parasitic transistor leakage, achieving a voltage drop of approximately 3.6 V with minimal current leakage.
Implementation Method 1
The diode string provides a voltage drop in a circuit when the diode string is turned on in a forward bias condition, which can be used as a voltage adapter
Implementation Method 2
A diode string voltage adapter is designed with a substrate of a first conductive type, featuring diodes with deep and second well regions that are electrically floating, and heavily doped regions to minimize leakage current
Implementation Method 3
the deep and second well regions not requiring connection to a voltage, thus preventing parasitic transistor activation
Data Source
AI summary
A diode string voltage adapter includes diodes formed in a substrate of a first conductive type. Each diode includes a deep well region of a second conductive type formed in the substrate. A first well region of the first conductive type formed on the deep well region. A first heavily doped region of the first conductive type formed on the first well region. A second heavily doped region of the second conductive type formed on the first well region. The diodes are serially coupled to each other. A first heavily doped region of a beginning diode is coupled to a first voltage. A second heavily doped region of each diode is coupled to a first heavily doped region of a next diode. A second heavily doped region of an ending diode provides a second voltage. The deep well region is configured to be electrically floated.