HEMT Sub-Channel Doping for Leakage Suppression
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Solution Overview
Problem
High-electron mobility transistors (HEMTs) experience unwanted leakage currents during the off-state due to minority carrier flow in sub-channel regions, leading to increased power losses.
Innovation Solution
A semiconductor substrate with a vertically varying dopant concentration of deep energy acceptor dopant atoms is introduced at interfaces between type III-V material regions, compensating for negative polarization charges and suppressing minority carrier channels, thereby reducing lateral and vertical off-state leakage currents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If HEMT device is operated in off-state, then power consumption is reduced, but unwanted leakage currents arise due to minority carrier flow in sub-channel region
Solution Approach 1:
The patent applies local quality by introducing a vertically varying dopant concentration profile specifically in the sub-channel region beneath the two-dimensional charge carrier gas channel. The dopant concentration is locally increased at the first interface between type III-V material regions to suppress minority carrier channels, while maintaining low doping in the active channel region to preserve high electron mobility. This localized doping strategy selectively suppresses leakage currents without degrading the on-state performance of the HEMT.
Solution Approach 2:
The patent implements parameter changes by modifying the dopant concentration parameter in the sub-channel region. Specifically, the dopant concentration is varied vertically with a local maximum at the first interface, creating energy barriers that suppress minority carrier flow. This parameter modification transforms the sub-channel region from a leakage pathway into a blocking region, effectively reducing off-state leakage currents while maintaining the overall device functionality.
2Object-generated harmful factors
If vertically varying dopant concentration is introduced at first interface, then minority carrier channels are suppressed, but device structure becomes more complex
Solution Approach 1:
The patent applies segmentation by dividing the dopant concentration profile into distinct vertical zones: a first region with increasing dopant concentration toward the first interface, a second region with the local maximum concentration at the interface, and a third region with decreasing concentration. This segmented approach allows precise control of minority carrier suppression at the critical interface while maintaining simplicity in other device regions. The segmentation enables independent optimization of leakage suppression and device performance without requiring complex modifications throughout the entire structure.
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 solution effectively eliminates or suppresses minority carrier channels, significantly reducing off-state leakage currents and associated power losses in HEMTs.
Implementation Method 1
a first interface in the semiconductor substrate between a first region of type III-V material and a second region of type III-V material that is disposed below the first region of type III-V material, wherein the first and second regions of type III-V material form polarization charges on either side of the first interface
Implementation Method 2
semiconductor substrate comprises a vertically varying dopant concentration of deep energy acceptor dopant atoms that is locally increased at the first interface
Data Source
AI summary
A semiconductor device includes a semiconductor substrate including a barrier region, a channel layer disposed below the barrier region and forming a heterojunction with the barrier region such that a two-dimensional charge carrier gas channel is disposed in the channel layer near the heterojunction, and a sub-channel region disposed below the channel layer, and a first interface in the semiconductor substrate between a first region of type III-V material and a second region of type III-V material that is disposed below the first region of type III-V material, wherein the first and second regions of type III-V material form polarization charges on either side of the first interface, wherein the first interface is within or formed by the sub-channel region, and wherein semiconductor substrate has a vertically varying dopant concentration of deep energy acceptor dopant atoms that is locally increased at the first interface.