Paper
8 February 2007 Quantum 1/f noise in GaN FETs, HFETs, MODFETs, and their oscillators' phase noise
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Abstract
GaN-based FETs, HFETs and MODFETs are ideally suited for use in high-power amplifiers and oscillators, due to their large band gap and high operating voltages. According to the quantum 1/f theory, the larger effective mass implied for the carriers also leads to lower fundamental 1/f noise and to lower resulting phase noise close to the carrier frequency. We have therefore studied the quantum 1/f noise sources in the channel and in the gate insulation. For the channel, a combination of conventional and coherent Quantum 1/f Effect (Q1/fE) is present, with the conventional Q1/fE dominant in the sub-threshold part of the channel toward the drain. It turns out that the quantum 1/f parameter "s" that determines the fraction of the two forms of Q1/fE, is no longer increasing proportionally to the width of the device w, when the latter exceeds the length of the channel. A logarithmic dependence on w is obtained for s instead. This is why an extremely large width w does not automatically lead to coherent Q1/fE in HFETs. Conventional Q1/fE applies for the gate insulation, with contributions of the much larger piezoelectric Q1/fE in spontaneously polarized AlGaN, if gate leakage is present. The noise figure is calculated, including all contributions. Finally, the minimal expected oscillator phase noise is calculated from the Q1/fE in the dissipative elements, even for perfectly linear amplifiers, by multiplication with the inverse fourth power of the quality factor, as was first done by us for quartz in 1979.
© (2007) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Peter H. Handel, Amanda M. Hall, and Hadis Morkoç "Quantum 1/f noise in GaN FETs, HFETs, MODFETs, and their oscillators' phase noise", Proc. SPIE 6473, Gallium Nitride Materials and Devices II, 64730O (8 February 2007); https://doi.org/10.1117/12.703257
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KEYWORDS
Field effect transistors

Resistance

Oscillators

Amplifiers

Quantum physics

Gallium nitride

Scattering

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