Substrate Impurity Incorporation Mitigation for Improved AlGaN/GaN-ON-Si RF Performance

A conductive interface is formed between Silicon substrate and AlN nucleation layer during high-temperature deposition. This parasitic conduction path is highly detrimental as it is capacitively coupled to the GaN HEMT 2DEG channel. Moreover, the presence of significant lattice mismatch and thermal mismatch between the AlN nucleation layer and Si leads to a very large threading dislocation density (TDD) within the AlN layer thereby creating a leakage path, significant electron scattering, and charge carrier trap centers. The parasitic conduction path dissipates the radio-frequency (RF) signal, which increases with operation frequency, in transistors manufactured on such a lossy Si substrate and large TDD AlN nucleation layer. As a result, they fail to deliver good RF amplifier performance at high frequency in terms of gain, power, and efficiency. This undesirable conductive path is suppressed after developing and optimizing a robust novel interface technology, and the AlN nucleation layer materials are significantly improved. As a result, the RF signal loss on AlGaN/GaN on Silicon materials is reduced substantially, well below 0.4 dB/mm for frequencies up to 50 GHz, compared to conventional AlGaN/GaN on Silicon heterostructures. For AlGaN/GaN HEMTs, this improvement of the RF performance is critical for high-power/high-frequency operation with enhancements to RF switching speed, power, gain, and efficiency.

Name thesis:degree_name

Doctor of Philosophy

Level thesis:degree_level

Doctoral

Discipline thesis:degree_discipline

Engineering

Grantor

Texas State University

Year dc:date.issued

2021

Author dc:creator

• Saha, Rony

Advisors dc:contributor.advisor

• Piner, Edwin L.
• Droopad, Ravindranath

Committee members dc:contributor.committeemember

• Holtz, Mark
• Smith, Casey
• Hanks, Craig

• RF loss GaN HEMT
• AlN
• substrate impurity

Language dc:language.iso

en

Handle dc:identifier.uri

https://hdl.handle.net/10877/17832

OAI identifier oai:identifier

oai:digital.library.txst.edu:10877/17832