论文信息 - Analysis of DC-RF dispersion in AlGaN/GaN HFETs using pulsed I-V and time-domain waveform measurements

Analysis of DC-RF dispersion in AlGaN/GaN HFETs using pulsed I-V and time-domain waveform measurements

AlGaN/GaN HFETs have been analyzed using pulsed I-V measurements and RF time-domain measurements in an attempt to analyze the phenomenon of DC-RF dispersion and achieve maximum RF performance. The pulsed I-V measurements exhibited the common problem of current slump, as did the RF power performance of the device. The RF time-domain waveforms are used to show that the RF knee-walkout increases with drain bias voltage, thus negating any improved power and efficiency performance that a larger voltage swing would achieve. It was also found that the degree of RF knee-walkout changes depending on the class of operation of the device. Although current slump is evident, it is not permanent, and there is negligible degradation of the device after prolonged RF stimulus.

[1] V. Tilak,et al. High-power broadband AlGaN/GaN HEMT MMICs on SiC substrates , 2001, 2001 IEEE MTT-S International Microwave Sympsoium Digest (Cat. No.01CH37157).

[2] L. Eastman,et al. The effect of surface passivation on the microwave characteristics of undoped AlGaN/GaN HEMTs , 2000, IEEE Electron Device Letters.

[3] P. J. Tasker,et al. A Vector Corrected High Power On-Wafer Measurement System with a Frequency Range for the Higher Harmomcs up to 40 GHz , 1994, 1994 24th European Microwave Conference.

[4] U. Mishra,et al. The impact of surface states on the DC and RF characteristics of AlGaN/GaN HFETs , 2001 .

[5] R. Coffie,et al. High-power polarization-engineered GaN/AlGaN/GaN HEMTs without surface passivation , 2004, IEEE Electron Device Letters.

[6] U. Mishra,et al. 30-W/mm GaN HEMTs by field plate optimization , 2004, IEEE Electron Device Letters.

[7] Paul J. Tasker,et al. High power time domain measurement system with active harmonic load-pull for high efficiency base station amplifier design , 2000, IMS 2000.