Schottky Diode Substrate Current Management
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In high-integrated Integrated Circuits (ICs), Schottky diodes integrated with transistors and control circuits on a semiconductor substrate face challenges due to parasitic bipolar junction transistors (BJTs) forming, which can lead to latch-up and substrate injection currents, disrupting the operation of other integrated components.
Innovation Solution
The implementation of a semiconductor device with a Schottky diode and a parasitic PN diode, along with a voltage limit circuit or control circuit that limits the forward voltage of the Schottky diode between its conduction threshold and the parasitic PN diode's conduction threshold, preventing the parasitic BJT from turning on and thus eliminating substrate injection currents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If Schottky diodes are integrated with transistors and control circuits in a single semiconductor substrate, then device integration and compactness are improved, but parasitic BJTs are formed causing latch-up and substrate injection currents that disrupt operation
Solution Approach 1:
A PN diode is introduced as an intermediary component between the Schottky diode and the semiconductor substrate. This PN diode acts as a mediator that captures and redirects substrate injection currents, preventing them from reaching and activating parasitic BJTs. The PN diode's anode is connected to the Schottky diode's anode, and its cathode is connected to the substrate, creating a controlled current path that eliminates the harmful latch-up effect while maintaining high integration.
2Power
If forward voltage of Schottky diode is increased to improve current carrying capacity, then power handling is improved, but parasitic BJT turns on causing latch-up
Solution Approach 1:
The PN diode serves as a protective intermediary that becomes conductive before the parasitic BJT can activate. By connecting the PN diode in parallel with the Schottky diode (anode to anode, cathode to substrate), it provides a preferred current path that limits the voltage across the Schottky diode to below the parasitic BJT turn-on threshold, allowing high current operation without latch-up.
Solution Approach 2:
The PN diode is configured to activate in advance of the parasitic BJT by providing a lower impedance current path at lower voltages. This preliminary action prevents the conditions necessary for parasitic BJT activation from occurring, effectively counteracting the potential harmful effect before it can manifest.
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 solution effectively prevents parasitic BJT activation, ensuring stable operation of Schottky diodes and other integrated components by maintaining the forward voltage within specific thresholds, maximizing current carrying capacity while preventing substrate injection.
Implementation Method 1
a Schottky diode formed in the semiconductor substrate
Implementation Method 2
parasitic bipolar junction transistors (BJT) may be formed in the semiconductor substrate
Data Source
AI summary
An electronic device with substrate current management. The electronic device has a semiconductor substrate in which a Schottky diode is formed. A parasitic PN diode is also formed in the semiconductor substrate, and coexisted with the Schottky diode in parallel. The forward voltage of the Schottky diode is limited to be larger than the forward conduction threshold voltage of the Schottky diode and to be smaller than the forward conduction threshold voltage of the parasitic PN diode.