The industry standard advanced SPICE model (ASM)-GaN compact model has been enhanced to model the GaN high electron mobility transistors (HEMTs) at extreme temperature conditions. In particular, the temperature dependence of the trapping behavior has been considered and a simplifying approximation in the temperature modeling of the saturation voltage in the ASM-GaN model has been relaxed. The enhanced model has been validated by comparing the simulation results of the model with the dc I-V measurement results of a GaN HEMT measured with chuck temperatures ranging from 22 • C to 500 • C. A detailed description of the modeling approach is presented. The new formulation of the ASM-GaN compact model can be used to simulate the circuits designed for extreme temperature environments. Index Terms-Compact models, gallium nitride, high electron mobility transistors (HEMTs), high-temperature modeling, physics-based models, semiconductor device measurement, semiconductor device modeling. I. INTRODUCTION G aN-BASED HEMT devices have demonstrated outstanding performance across a wide range of RF and power applications during recent times. The literature [1]-[3] shows increasingly aggressive scaling of GaN devices, which has resulted in very promising high-speed devices with gate lengths as small as 20 nm and f T / f max exceeding 400 GHz [4]. Furthermore, the GaN power devices that can reliably operate with the drain-source voltage (V DS) values of 600-650 V are widely available where they set the current benchmark for commercial GaN power devices.
This letter describes the design and the realization of a fixed-frequency oscillator and voltage-controlled oscillator (VCO) MMIC realized in an AlGaN/GaN HEMT technology with 100 nm gate length. Both oscillators achieve output power levels of almost 20 dBm without post-amplification. The oscillation frequency of the fixed-frequency oscillator is 65.6 GHz, while the VCO can be tuned from 65.6 to 68.8 GHz, which leads to a relative bandwidth of 5%. The phase noise of the VCO is dBc/Hz at 1 MHz frequency offset. Index Terms-Gallium Nitride (GaN), high electron mobility transistor (HEMT), monolithically microwave integrated circuit (MMIC), V-band (50-75 GHz), voltage-controlled oscillator (VCO).
This paper reports on two wide bandwidth monolithic power amplifiers suitable for electronic warfare (EW) systems and other wide bandwidth applications up to the Qband. The MMICs are based on a 100 nm AlGaN/GaN T-gate HEMT microstrip transmission line MMIC technology with an fT > 80 GHz. Both designed and fabricated amplifiers use the non-uniform distributed power amplifier (NDPA) topology and cover a frequency range from 8 GHz to 42 GHz, whereas the lower band edge is limited by the on-chip DC bias network. The first MMIC is a single-stage topology with a measured S21 of 6 ± 1 dB, the second a dual-stage topology with a measured S21 of 14 ± 2 dB, both over the entire frequency range. By choosing adequate device geometries and a low interstage impedance of 32 Ω in the dual-stage design, the wide bandwidth and high saturated output power of > 0.5 W of the single-stage design are maintained. A large-signal state-space model was used in the design process. A large-signal methodology for the broadband design of the amplifiers given soft compression of the FETs and low PAE over large bandwidth is proposed and verified.
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