HEMT Resistor Structure With Barrier-Side Electrode Contact

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Solution Overview

Problem

Conventional resistor structures in high electron mobility transistors (HEMTs) face challenges with current leakage due to the direct contact of electrodes with the p-type semiconductor layer, which affects the overall performance and reliability of the devices.

Innovation Solution

A resistor structure is fabricated by forming a p-type semiconductor layer on a barrier layer, trimming the barrier layer to create a slight width difference with the buffer layer, and then forming source and drain electrodes on both the barrier and buffer layers, which improves current leakage by altering the electrode placement and contact points.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If electrodes are placed directly on the p-type semiconductor layer, then electrical contact is achieved, but current leakage increases

Engineering Contradiction:

Improvecurrent leakage resistanceVSAvoidelectrode placement structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent transitions from conventional planar electrode placement to a three-dimensional structure where electrodes are positioned on the sidewalls of the barrier layer. This dimensional change allows electrodes to contact the p-type semiconductor layer through the barrier layer's lateral surfaces, establishing electrical connection while preventing direct top-surface contact that causes leakage.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The barrier layer serves as an intermediary structure between the electrodes and the p-type semiconductor layer. By trimming the barrier layer to create exposed sidewalls, the patent uses this intermediate layer to mediate electrical contact while its removed portions prevent direct leakage paths, thus resolving the contradiction between achieving contact and preventing leakage.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If the barrier layer width is reduced by trimming, then current leakage is improved, but manufacturing precision requirements increase

Engineering Contradiction:

Improvecurrent leakage resistanceVSAvoidbarrier layer trimming precision

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The barrier layer trimming is performed as a preliminary action before electrode formation. By pre-trimming the barrier layer to expose appropriate sidewall areas, the patent prepares the structure in advance, allowing electrodes to be subsequently formed with standard precision rather than requiring ultra-precise alignment during electrode fabrication.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The trimming process applies local quality modification by selectively removing barrier layer material only in specific regions to expose sidewalls. This localized modification achieves the leakage prevention function without requiring uniform high-precision trimming across the entire structure, thereby reducing overall manufacturing precision requirements.

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS20240006468A1Resistor structure and method for fabricating the same

Publication Date: 2024.01.04 UNITED MICROELECTRONICS CORP

AI summary

A method for fabricating a resistor structure includes the steps of forming a buffer layer on a substrate, forming a barrier layer on the buffer layer, forming a p-type semiconductor layer on the barrier layer, patterning the p-type semiconductor layer, trimming the barrier layer along a first direction, and then forming an electrode on the barrier layer along a second direction.