Generalized Frequency Dependent Small Signal Model for High Frequency Analysis of AlGaN/GaN MOS-HEMTs

• Published in: IEEE journal of the Electron Devices Society Vol. 9; pp. 570 - 581
• Main Authors: Jadhav, Aakash, Ozawa, Takashi, Baratov, Ali, Asubar, Joel T., Kuzuhara, Masaaki, Wakejima, Akio, Yamashita, Shunpei, Deki, Manato, Honda, Yoshio, Roy, Sourajeet, Amano, Hiroshi, Sarkar, Biplab
• Format: Journal Article
• Language: English
• Published: New York IEEE 2021; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Aluminum gallium nitride; Aluminum gallium nitrides; Curve fitting; Equivalent circuits; Frequency analysis; Functions (mathematics); Gallium nitrides; HEMTs; High electron mobility transistors; high electron mobility transistors (HEMTs); High frequencies; High frequency; Integrated circuit modeling; least squares methods; lumped model; Mathematical model; Metal oxide semiconductors; Model accuracy; MODFETs; MOS devices; Polynomials; Semiconductor devices; Topology; unity gain frequency; Wide band gap semiconductors; Y-parameters
• ISSN: 2168-6734; 2168-6734
• DOI: 10.1109/JEDS.2021.3081463

Traditional lumped small signal equivalent circuit models of AlGaN/GaN metal oxide semiconductor high electron mobility transistors (MOS-HEMTs) are made up of constant valued circuit elements. Such models are unable to capture the high frequency behavior (above 20 GHz) of the device. In this work, a modified small signal equivalent circuit model of AlGaN/GaN MOS-HEMTs is presented. The key feature of the proposed model is that the values of the different circuit elements in the model are considered to be frequency dependent in nature and not constants. The frequency dependent value of each circuit element is mathematically represented using polynomial functions where the coefficients of the functions are determined via a least-square curve fitting approach. This frequency dependent attribute of the circuit element values ensures that the proposed model is very accurate at high frequencies without sacrificing the compactness of the model topology. The accuracy of the proposed model has been verified up to 50 GHz using experimentally measured Y-parameters of AlGaN/GaN MOS-HEMTs having a different gate dielectric and gate length.