InP- and GaN-based devices and MMICs for signal control and generation.

Abstract

Large communication bandwidths over long distances are desired for both military and commercial applications. These requirements demand the development of electronic devices and circuits with increased frequency and power capabilities. InP-based switching InGaAs PIN diodes, developed in this work, offered the advantages of lower turn-on voltage (&sim;<italic>0.4V</italic>) and higher switching cutoff frequency (&sim;<italic>9THz</italic>) compared with the GaAs-based diodes. These high-performance InGaAs PIN diodes were used to realize SPST and SPDT MMIC switches for millimeter-wave applications, such as W-band automotive radars. Low-parasitics MMIC technologies using InP-based microstrip and coplanar-waveguide transmission line were developed for this purpose. Microstrip-based W-band SPST switches employing one and two InGaAs PINs demonstrated low insertion loss of <italic>1.2dB</italic> and <italic>1.8dB</italic> and high isolation of <italic>23dB</italic> and <italic>35dB</italic>, respectively. A <italic>77GHz</italic> SPDT transceiver switch was realized using low-parasitics InGaAs PIN diode coplanar technology and had a record-high isolation of <italic> 43dB</italic> and a low insertion loss of <italic>1.6dB</italic>. Improved performance of InP-based InGaAs PIN diodes switches was accompanied by additional advantages of reduced power consumption (<italic>0.3mW</italic> per diode), high power handling (<italic>27dBm</italic>), and large modulation bandwidth (<italic>5Gps</italic>). The compatibility of InGaAs PIN diodes with high-frequency InP-based electronics also opens the possibility for building next generation D-band automotive radars and imaging radar systems. While GaAs devices have been successfully employed for signal control and generation, their power capabilities are limited, especially at the millimeter-wave range. Use of wide-bandgap semiconductors, such as GaN, with increased electrical strength offers the possibility to enhance the power performance. Thus, large-signal characterization of GaN-based power HFETs showed their high output power density (<italic>1W</italic>/<italic>mm</italic>) and excellent scalability. GaN-based MISFETs were realized and demonstrated their improved potential for power applications as confirmed by low interface-state density (<italic>10<super>11</super></italic> <italic>c<super>-2</super> eV<super> -1</super></italic>), high transconductance (<italic>185mS</italic>/<italic> mm</italic>) and current density (<italic>700mA</italic>/<italic>mm</italic>). A theoretical study was conducted to evaluate, for the first time, the microwave potential of GaN-based Gunn devices. Harmonic power analysis based on transient hydrodynamic simulations was developed and applied to investigate GaN Gunn diode oscillators. GaN Gunn diode oscillators were designed, and showed high output power of <italic>38dBm</italic> at <italic>90GHz</italic> corresponding to twice the frequency and a hundred-times the power capability of GaAs diodes.