Diode Structure Suppressing Parasitic Current via Transistor Competition
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Solution Overview
Problem
In semiconductor devices, unintended pn junctions and transistors can cause parasitic current, reducing efficiency and leading to issues like latchup, where current is diverted away from the intended path and can cause permanent damage.
Innovation Solution
A diode design that includes a parasitic transistor formed between one terminal and the substrate, with an additional lateral transistor competing to direct current flow, reducing parasitic current by diverting it away from the substrate and into a desired path using highly doped p-type regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If trench isolation is used to reduce parasitic current, then device reliability is improved, but manufacturing complexity and cost increase
Solution Approach 1:
The invention extracts and eliminates the parasitic transistor structure by modifying the doping configuration. Specifically, it removes the unintended pnp transistor formation by adjusting the doping types and concentrations in the drift region and contact structure, thereby taking out the harmful parasitic current path without requiring additional isolation trenches or complex manufacturing steps
Solution Approach 2:
The invention changes the doping parameters (type, concentration, depth) of the semiconductor regions to suppress parasitic current. By modifying the doping concentration in the drift region and contact structure, the parasitic transistor's gain is reduced below unity, preventing latchup while maintaining standard manufacturing processes
2Device complexity
If parasitic current is allowed to flow, then device complexity is reduced, but device efficiency deteriorates and latchup occurs
Solution Approach 1:
The invention converts the harmful parasitic current into a beneficial effect by designing the doping structure so that the parasitic transistor's operation actually helps suppress latchup. The modified doping configuration ensures that any parasitic current flow remains controlled and contributes to preventing sustained latchup conditions through inherent negative feedback mechanisms
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 diode design effectively reduces parasitic current flow, enhancing device efficiency and preventing latchup by diverting current into a desired path, thus improving the operational reliability and preventing damage.
Implementation Method 1
a second transistor is formed that competes with the parasitic transistor to direct current flow between the anode terminal and the cathode terminal
Implementation Method 2
reducing parasitic current by diverting it away from the substrate and into a desired path
Data Source
AI summary
A diode conducts current between an anode terminal and a cathode terminal. The diode includes a parasitic transistor formed between one of the terminals and the substrate. The diode also includes a second transistor that competes with the parasitic transistor to direct current flow between the anode terminal and the cathode terminal.