Vertically Integrated pHEMTs with Isolation Layer
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Solution Overview
Problem
Conventional pseudomorphic high electron mobility transistors (pHEMTs) struggle to optimize performance in both enhancement and depletion modes independently, limiting their functionality in semiconductor devices, and there is a need for reduced package size and cost.
Innovation Solution
A semiconductor device with vertically integrated pHEMTs, featuring a substrate, a lower pHEMT structure, an isolation layer, and an upper pHEMT structure, where the isolation layer separates the lower and upper pHEMTs to allow independent operation, enabling different modes and sizes for optimal performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single channel is used for both enhancement mode and depletion mode pHEMTs, then device complexity is reduced, but performance optimization for both modes independently becomes impossible
Solution Approach 1:
The patent divides a single pHEMT structure into two independent channels: a first channel configured for enhancement mode operation and a second channel configured for depletion mode operation. Each channel has its own gate electrode and channel region, allowing independent performance optimization for each mode while sharing the same device structure.
Solution Approach 2:
The patent creates a universal pHEMT device that can perform both enhancement mode and depletion mode functions within a single structure. The device incorporates dual channels that enable it to serve multiple functional purposes (low noise amplification and high-speed switching) without requiring separate devices.
2Area of stationary object
If different transistors are integrated into a single semiconductor device, then package size and cost are reduced, but isolation of integrated transistors becomes necessary for different functions
Solution Approach 1:
The patent transitions from lateral integration to vertical integration by stacking the first pHEMT structure and second pHEMT structure in different vertical layers. This vertical arrangement allows both enhancement mode and depletion mode transistors to be integrated in a compact footprint while maintaining functional isolation through the layered structure and intermediate isolation layers.
3Adaptability or versatility
If pHEMTs operate in different modes for different functions, then functional versatility is improved, but independent performance optimization becomes difficult with conventional structures
Solution Approach 1:
The patent applies different structural characteristics to different channels within the same device. The first channel has parameters optimized for enhancement mode operation (such as gate length, channel width, and barrier layer composition), while the second channel has parameters optimized for depletion mode operation, allowing each channel to achieve optimal performance for its specific function.
Data Source
AI summary
The present disclosure relates to a semiconductor device with vertically integrated pseudomorphic high electron mobility transistors (pHEMTs). The disclosed semiconductor device includes a substrate, a lower pHEMT structure with a lower pHEMT, an isolation layer, and an upper pHEMT structure with an upper pHEMT. The lower pHEMT structure is formed over the substrate and has a first region and a second region that is laterally disposed with the first region. The lower pHEMT is formed in or on the second region. The isolation layer resides over the first region. The upper pHEMT structure is formed over the isolation layer and does not extend over the second region. Herein, the isolation layer separates the lower pHEMT structure from the upper pHEMT structure such that the lower pHEMT and the upper pHEMT operate independently from each other.