Lateral Semiconductor Device Space-Charge Layer Design
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Solution Overview
Problem
Current power semiconductor devices face challenges in achieving high breakdown voltage with minimal on-resistance due to non-uniform electric fields and premature breakdown, particularly in lateral geometry devices like FETs, where efficient control over space-charge distribution is difficult, leading to limitations in device performance and operating frequency.
Innovation Solution
A lateral semiconductor device design incorporating a space-charge generating layer on the opposite side of the device channel, which forms a space-charge region to deplete the channel in response to operating voltage, allowing for reduced electric field components and increased breakdown voltage while maintaining low on-resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the gate-drain spacing distance is increased to increase breakdown voltage, then the breakdown voltage is improved, but the device exhibits breakdown voltage-gate-drain spacing dependence saturation at high voltages
Solution Approach 1:
The patent introduces a vertical space-charge generating layer beneath the lateral device channel, transitioning from purely lateral field control to a combined vertical-lateral control mechanism. This dimensional change allows the electric field to be modulated in the vertical direction through the space-charge layer, enabling higher breakdown voltages without proportionally increasing the gate-drain spacing distance.
2Reliability
If field plates are used to decrease peak electric field near the gate electrode edge, then the breakdown voltage is increased, but the device suffers from premature breakdown between the field plates and the drain electrode
Solution Approach 1:
The patent introduces a space-charge generating layer as an intermediary structure between the drain electrode and the device channel. This layer generates a distributed space-charge region that acts as a field-modulating medium, replacing the discrete field plate structure. The space-charge layer provides continuous field control without creating high-voltage stress points that cause premature breakdown.
3Reliability
If field plates are used to control electric field distribution, then the breakdown voltage is improved, but the inter-electrode and electrode-semiconductor capacitances increase
Solution Approach 1:
The patent changes the fundamental parameter of field control from using conductive field plates with significant capacitance to using a space-charge generating layer with controllable charge density. By modulating the space-charge density in the layer, the electric field distribution is controlled without introducing large parasitic capacitances, thereby maintaining high-frequency operation capability while achieving improved breakdown voltage.
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 design achieves higher breakdown voltage and lower on-resistance, enabling improved performance in semiconductor devices by reducing electric field components to their theoretical minimum, suitable for high-voltage applications.
Implementation Method 1
The space-charge generating layer has a set of attributes configured to form a space-charge region to at least partially deplete the device channel in response to an operating voltage being applied to the first contact and the second contact
Data Source
AI summary
A lateral semiconductor device and/or design including a space-charge generating layer and electrode located on an opposite side of a device channel as contacts to the device channel is provided. The space-charge generating layer is configured to form a space-charge region to at least partially deplete the device channel in response to an operating voltage being applied to the contacts to the device channel.