Nitride HEMT Oxide Layer Structure for Source Starvation Suppression
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Solution Overview
Problem
The source starvation effect occurs in nitride semiconductor HEMTs due to insufficient two-dimensional electron gas density on the source electrode side when switching from the off-state to the on-state, limiting the drain current and output power and frequency performance.
Innovation Solution
A semiconductor device configuration that includes a first and second nitride semiconductor layer, source, drain, and gate electrodes, a protective film, and specifically positioned oxide layers to form electric dipoles that enhance two-dimensional electron gas density by adjusting oxygen area densities across oxide layers, thereby suppressing the source starvation effect.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the gate length is shortened to raise output power and frequency, then the operability at high output and high frequency is improved, but the source starvation effect occurs due to insufficient 2DEG density on the source electrode side
Solution Approach 1:
The patent changes the physical and chemical parameters of the oxide layers by controlling oxygen area density to form electric dipoles. This modifies the electrical characteristics of the semiconductor device, increasing 2DEG density in the region between the gate and source electrodes, thereby suppressing the source starvation effect while maintaining short gate length for high frequency operation
Solution Approach 2:
The patent introduces oxide layers as intermediary structures between the gate electrode and source electrode. These oxide layers with controlled oxygen area density act as mediators that generate electric dipoles, which in turn enhance 2DEG density and improve carrier supply to the channel region
2Power
If the gate length is shortened to improve output power, then the power amplification capability is improved, but the drain current value becomes less than expected due to source starvation effect
Solution Approach 1:
The patent modifies the oxygen area density parameter in oxide layers to create electric dipoles that enhance 2DEG density, ensuring sufficient drain current even when gate length is shortened for high output power operation
Solution Approach 2:
The patent applies preliminary action by forming oxide layers with specific oxygen area density before device operation. This pre-established dipole structure counteracts the source starvation effect that would otherwise occur during high-power switching operations
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 semiconductor device effectively suppresses the source starvation effect, improving the two-dimensional electron gas density and enhancing the output power and frequency performance of nitride semiconductor HEMTs.
Implementation Method 1
form electric dipoles that enhance two-dimensional electron gas density by adjusting oxygen area densities across oxide layers
Data Source
AI summary
A semiconductor device includes a first nitride semiconductor layer and a second nitride semiconductor layer provided above the first nitride semiconductor layer and forming a two-dimensional electron gas between the first nitride semiconductor layer and the second nitride semiconductor layer. Above the second nitride semiconductor layer, a source electrode and a drain electrode electrically connected to the two-dimensional electron gas, and a gate electrode arranged between the source electrode and the drain electrode are provided. Between the gate electrode and the source electrode, a first oxide layer and a second oxide layer provided above the first oxide layer are formed.