Sense Diode Recovery Current Suppression via Resistance Layer
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Solution Overview
Problem
The existing semiconductor devices with a sense diode and switching element on a common substrate face high recovery currents due to parasitic capacitance, which can lead to increased load on the sense diode and potential reliability issues.
Innovation Solution
Incorporating a resistance layer with higher resistivity than the sense anode electrode, connected between the sense anode region and the upper main electrode, to reduce the forward current and subsequent recovery current through the sense diode by increasing the forward voltage drop and minimizing hole injection during forward voltage application.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the sense diode and switching element are provided on a single semiconductor substrate with both electrodes above the substrate, then the device integration is improved, but a parasitic capacitance exists between the upper main electrode and sense anode electrode causing high recovery current
Solution Approach 1:
A parasitic capacitance compensation circuit is introduced as an intermediary element between the sense diode and the upper main electrode. This compensation circuit generates a compensating signal that counteracts the effect of parasitic capacitance, thereby reducing the recovery current while maintaining the integrated structure.
Solution Approach 2:
The patent modifies electrical parameters by introducing a compensation current that changes in magnitude and direction based on the switching state. During the off-state of the switching element, the compensation circuit adjusts the voltage parameter at the sense anode electrode to counterbalance the parasitic capacitance discharge, thereby controlling the recovery current.
2Device complexity
If the sense anode electrode is directly connected to the upper main electrode, then the connection simplicity is improved, but the forward voltage drop is reduced causing excessive forward current and hole injection
Solution Approach 1:
A resistance element is introduced as an intermediary between the sense anode electrode and the upper main electrode. This resistance element limits the forward current by creating an appropriate voltage drop during the on-state, thereby reducing excessive hole injection into the semiconductor substrate while maintaining connection functionality.
3Measurement precision
If the sense diode is used to detect switching element state, then the measurement capability is improved, but the sense diode experiences high load reducing reliability
Solution Approach 1:
The parasitic capacitance compensation circuit acts as a mediator that protects the sense diode from high load conditions. By compensating for the parasitic capacitance discharge, the circuit reduces the current stress on the sense diode during switching transitions, thereby improving reliability while maintaining detection capability.
Solution Approach 2:
The patent dynamically changes the voltage parameter at the sense anode electrode through the compensation circuit. During critical switching moments, the compensation circuit adjusts the voltage to prevent excessive current flow through the sense diode, thereby protecting it while maintaining measurement functionality.
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 configuration effectively suppresses the recovery current in the sense diode, reducing the load on it and enhancing its reliability by limiting hole injection and discharge, thereby improving the overall performance and longevity of the semiconductor device.
Implementation Method 1
a parasitic capacitance exists between the upper main electrode and the sense anode electrode... when a potential of the upper main electrode 120 is higher than a potential of the lower main electrode 130, a potential of the sense anode electrode 140 is increased due to capacitance coupling via the parasitic capacitance 150
Implementation Method 2
Incorporating a resistance layer with higher resistivity than the sense anode electrode, connected between the sense anode region and the upper main electrode, to reduce the forward current and subsequent recovery current through the sense diode by increasing the forward voltage drop
Data Source
AI summary
A semiconductor device provided herein includes: a semiconductor substrate; an upper main electrode provided above the semiconductor substrate; a sense anode electrode provided above the semiconductor substrate; a resistance layer provided above the semiconductor substrate and having a resistivity higher than the sense anode electrode; a lower main electrode provided below the semiconductor substrate. The semiconductor substrate includes a switching element and a sense diode. The switching element is connected between the upper main electrode and the lower main electrode. The sense diode comprises a first anode region of a p-type connected to the sense anode electrode via the resistance layer and a first cathode region of an n-type connected to the lower main electrode.