HEMT Gate Recess Structure for Lower RON and Higher Breakdown
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Solution Overview
Problem
Conventional high electron mobility transistors (HEMTs) face challenges in achieving reduced on-resistance (RON), increased transconductance (gm), and improved breakdown voltage (VBR) to meet industry requirements.
Innovation Solution
A semiconductor device design featuring a substrate with a semiconductor channel layer and a semiconductor barrier layer, where the barrier layer includes a recess and a gate electrode with a body portion and vertical extension portions overlapping the recess, enhancing the 2-DEG region's carrier concentration and electric field distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional HEMT structures are used, then the device can be manufactured with standard processes, but the on-resistance is high and transconductance is limited
Solution Approach 1:
The gate electrode is divided into a body portion and vertical extension portions that extend into recesses of the barrier layer. This segmentation allows different regions of the gate to perform different functions: the body portion provides overall gate control while the vertical extension portions locally enhance carrier concentration and electric field at the channel interface, thereby reducing on-resistance and increasing transconductance without requiring entirely new manufacturing processes
Solution Approach 2:
The gate electrode structure transitions from a planar two-dimensional configuration to a three-dimensional structure with vertical extension portions that protrude into recesses of the barrier layer. This dimensional change increases the gate's effective surface area and its interaction with the 2-DEG layer, enabling enhanced carrier concentration and electric field distribution that improve electrical performance
2Reliability
If the barrier layer thickness is increased to improve breakdown voltage, then VBR increases, but the electric field distribution becomes less optimized
Solution Approach 1:
The barrier layer is designed with non-uniform thickness featuring recesses that create locally thinner regions. The vertical extension portions of the gate electrode are positioned to overlap these recesses, creating localized zones of enhanced electric field and carrier concentration. This local quality variation allows the overall structure to maintain high breakdown voltage from the thicker barrier regions while achieving optimized electric field distribution at the channel interface through the thinner recess regions
Solution Approach 2:
The barrier layer thickness parameter is varied spatially to create regions of different thickness. By changing the thickness parameter from uniform to non-uniform with specific recess depths and positions, the electric field distribution is optimized while maintaining adequate breakdown voltage. The vertical extension portions further modify the effective gate-to-channel distance parameter in the recess regions to enhance carrier concentration
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 design effectively reduces on-resistance, increases transconductance, and improves breakdown voltage, leading to enhanced electrical performance of HEMTs.
Implementation Method 1
enhancing the 2-DEG region's carrier concentration and electric field distribution
Data Source
AI summary
A semiconductor device includes a substrate, a semiconductor channel layer, a semiconductor barrier layer, and a gate electrode. The semiconductor channel layer is disposed on the substrate, and the semiconductor barrier layer is disposed on the semiconductor channel layer, where the surface of the semiconductor barrier layer includes at least one recess. The gate electrode is disposed on the semiconductor barrier layer and includes a body portion and at least one vertical extension portion overlapping the recess.