Nitride Semiconductor Device With Drift Layer Groove For Avalanche Energy Management
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Solution Overview
Problem
Conventional semiconductor devices with nitride semiconductors have a low avalanche energy capacity due to electric field concentration at the gate groove, leading to premature transistor failure when switching off with inductive loads.
Innovation Solution
The semiconductor device design includes a substrate with a groove in the drift layer, an underlayer, an electron transit layer, an electron supply layer, and a channel layer configuration that reduces electric field concentration by altering the distance from the gate electrode to the substrate, allowing avalanche current to flow through a p-n junction rather than a two-dimensional electron gas layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the distance from the gate groove to the substrate is shortened, then the manufacturing process is simplified, but electric field concentration increases causing premature transistor failure
Solution Approach 1:
The patent segments the electric field management function by creating two separate groove structures: the gate groove for pinch-off control and a separate groove in the drift layer for avalanche energy management. This segmentation allows each structure to be optimized independently - the gate groove can be formed to standard specifications while the drift layer groove provides additional electric field control to prevent concentration-related failures.
Solution Approach 2:
The groove formed in the drift layer acts as an intermediary structure that mediates between the gate groove and the substrate. It provides an intermediate region that modifies the electric field distribution, preventing direct concentration at the gate groove while still allowing the overall compact structure to be maintained for manufacturing efficiency.
2Device complexity
If avalanche current passes through the two-dimensional electron gas layer, then the transistor structure is simple, but energy density increases causing local temperature elevation and fracture
Solution Approach 1:
The patent changes the physical parameters of the drift layer by forming a groove that modifies the current path and electric field distribution during avalanche breakdown. This parameter change redirects the avalanche current away from the two-dimensional electron gas layer, reducing the energy density and heat generation in that region while maintaining the overall structural simplicity of the device.
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 enhances the avalanche energy capacity and breakdown voltage of the semiconductor device, reducing energy density and preventing transistor failure during energy consumption from inductive loads.
Implementation Method 1
an avalanche current passes from drain electrode D to source electrode S through channel layer 122
Implementation Method 2
Channel layer 122 forms a two-dimensional electron gas layer generated at an interface between an AlGaN layer and a GaN layer
Implementation Method 3
electric field concentration occurs to the gate groove and, in particular, an end portion of the gate groove
Data Source
AI summary
A semiconductor device includes: a substrate; a drift layer which is disposed on the substrate and has a groove; an underlayer which is disposed above the drift layer; a first opening which penetrates the underlayer to reach the drift layer; an electron transit layer and an electron supply layer which are disposed to cover the first opening; a second opening which penetrates the electron supply layer and the electron transit layer to reach the underlayer; a gate electrode which is disposed above the electron supply layer at a position corresponding to a position of the first opening; a source electrode which is disposed to cover the second opening and in contact with the underlayer; and a drain electrode which is disposed on a backside surface of the substrate. A bottom surface of the groove is closer to the substrate than a bottom surface of the first opening.