Lateral Power Package Grounding for Substrate Leakage Control
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Solution Overview
Problem
GaN power HEMTs face challenges with substrate leakage and floating substrate voltage leading to back-gating and electron trapping effects, which degrade dynamic behavior and breakdown voltage, especially when operated at high frequency and high voltage.
Innovation Solution
Incorporating a resistor between the device substrate and the electrical ground point in the package to create a grounded path, reducing substrate leakage and mitigating back-gating and electron trapping effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If electrically insulating adhesive or insulating substrate is used to reduce substrate leakage, then substrate leakage is mitigated, but the substrate becomes floating with unsteady voltage, causing back-gating effect and electron trapping phenomenon
Solution Approach 1:
A resistor is introduced as an intermediary component between the substrate and ground. This resistor provides a controlled electrical path that allows the substrate to maintain a stable potential while still preventing harmful leakage currents. The resistor acts as a mediator that balances the conflicting requirements of electrical isolation and potential stabilization.
Solution Approach 2:
The electrical parameters of the substrate connection are changed from complete insulation (infinite resistance) to controlled resistance. By selecting an appropriate resistance value, the system achieves optimal balance between preventing substrate leakage and maintaining stable substrate voltage for reliable dynamic operation.
2Reliability
If high-resistivity GaN layer is increased to suppress vertical current leakage, then breakdown voltage improves, but material quality degrades due to carbon or iron doping limitations
Solution Approach 1:
The problem of achieving high resistivity through doping is extracted and relocated to an external resistor component. This allows the GaN layer to maintain optimal doping levels for material quality while the external resistor provides the necessary high resistance path to suppress leakage currents and improve breakdown voltage.
Solution Approach 2:
An external resistor serves as an intermediary that provides the high resistance function previously attempted to be achieved through material doping. This separates the electrical function (resistance) from the material structure, allowing optimal material quality while achieving the desired electrical characteristics.
3Reliability
If semi-insulating and thermally conductive glue is used to replace electrically insulating glue, then floating substrate is eliminated, but resistivity control becomes difficult to ensure consistent high yield
Solution Approach 1:
A discrete resistor component is used as an intermediary to provide the necessary resistance function. This approach replaces the difficult-to-control semi-insulating glue with a standard electronic component that has well-defined and controllable resistance values, significantly improving manufacturing consistency and yield.
Solution Approach 2:
The resistance parameter is changed from being an intrinsic property of the adhesive material (difficult to control) to an extrinsic property provided by a separate resistor component (easy to control). This allows for precise selection of resistance values and ensures consistent electrical characteristics across production batches.
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 resistor effectively suppresses substrate leakage current, improves breakdown voltage, and ensures consistent dynamic behavior by grounding the substrate, enhancing device performance.
Implementation Method 1
Incorporating a resistor between the device substrate and the electrical ground point in the package to create a grounded path, reducing substrate leakage
Implementation Method 2
The resistor effectively suppresses substrate leakage current, improves breakdown voltage, and ensures consistent dynamic behavior by grounding the substrate
Data Source
AI summary
A packaged lateral semiconductor device includes a resistor connected between the device substrate and a package ground point. The packaged device avoids the drawbacks of a floating substrate, and reduces substrate leakage current and increases breakdown voltage relative to conventionally packaged structures. Moreover, device substrate leakage current and breakdown voltage may be controlled by selecting a value of the resistor. Exemplary devices include high voltage lateral devices such as high-electron mobility transistors (HEMTs), implemented in technologies such as GaN or GaAs, where the packaging achieves high breakdown voltage with improved dynamic behavior.