III-V HEMT Substrate Capacitor Integration for Higher Capacitance Density
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Solution Overview
Problem
Incorporating passive components into semiconductor dies for power switching applications increases production costs due to the need for additional die area, which is particularly pronounced in type III-V semiconductor technology.
Innovation Solution
A semiconductor device with a monolithically integrated capacitor within the die, utilizing a type III-V semiconductor barrier layer as the dielectric medium and a two-dimensional charge carrier gas as an electrode, combined with metallization layers to form parallel plate capacitors, enhancing capacitance per area without significant increases in die size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If passive components are incorporated into the semiconductor die, then the input or output characteristics of the switching device are improved, but the die area increases and production cost increases
Solution Approach 1:
The patent merges the capacitor structure with the existing HEMT device structure by utilizing the barrier layer and channel layer that already form part of the transistor. The barrier layer serves dual purposes: as a structural component for the HEMT and as the dielectric medium for the capacitor, eliminating the need for separate passive component fabrication processes and reducing overall die area.
Solution Approach 2:
The barrier layer in the HEMT structure is given multi-functionality by serving both as a critical component for the high-electron mobility transistor operation and as the dielectric medium for the integrated capacitor. This universal usage of the barrier layer allows the same material and structure to fulfill multiple functions, reducing the need for additional components.
2Reliability
If passive components are incorporated into the semiconductor die, then the parasitic effects are reduced, but the production cost increases
Solution Approach 1:
The capacitor is merged with the HEMT fabrication process, using the same epitaxial growth steps to create both the transistor structure and the capacitor dielectric. This integration allows passive components to be formed during the same manufacturing sequence as the active device, reducing parasitic effects while avoiding the need for additional processing steps that would increase production cost.
3Reliability
If additional die area is consumed for passive components, then the input or output characteristics are improved, but the cost of producing each device increases
Solution Approach 1:
The patent transitions from lateral expansion to vertical utilization of space by stacking the capacitor structure vertically within the existing HEMT footprint. The capacitor is formed using the barrier layer and overlying dielectric layers in the vertical dimension, allowing passive components to be integrated without increasing the lateral die area, thereby maintaining cost-effectiveness while improving electrical characteristics.
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 allows for reduced cost and increased capacitance per area, effectively addressing the expense and space constraints of integrating passive components in type III-V semiconductor devices.
Implementation Method 1
a channel layer forming a heterojunction with the barrier layer such that a two-dimensional charge carrier gas is disposed in the channel layer near the heterojunction
Implementation Method 2
The two-dimensional charge carrier gas is used by the HEMT to conduct the load current of the device. Because a two-dimensional charge carrier gas has an extremely high carrier mobility
Implementation Method 3
a capacitor that is monolithically integrated into the semiconductor die and is disposed in a second lateral region of the semiconductor die, wherein a dielectric medium of the capacitor comprises a first section of the barrier layer
Data Source
AI summary
A semiconductor die includes a barrier layer of type III-V semiconductor material, a channel layer of type III-V semiconductor material disposed below the barrier layer, the channel layer forming a heterojunction with the barrier layer such that a two-dimensional charge carrier gas is disposed in the channel layer near the heterojunction, and a capacitor monolithically formed in the semiconductor die, wherein a dielectric medium of the capacitor includes a first section of the barrier layer.