High-breakdown-voltage Ga/sub 0.51/In/sub 0.49/P channel MESFET's grown by GSMBE
The first Ga/sub 0.51/In/sub 0.49/P channel MESFETs grown on a (100) GaAs substrate by GSMBE have been fabricated. A high gate-to-drain breakdown voltage of 42 V with a high maximum current density (320 mA/mm) was achieved. This result demonstrates that high-breakdown voltage could be attained by using Ga/sub 0.51/In/sub 0.49/P as the channel material. We also measured a high-maximum oscillation frequency (f/sub max/) of 30 GHz for a 1.5 /spl mu/m gate-length device. This value is quite high compared with other high-breakdown-voltage GaAs MESFET's or MISFET's with the same gate length.
High-Linearity High-Current-Drivability Gao.5 1 Ino.49P/GaAs MISFET Using Gao.5 1 Ino.49P Airbridge Gate Structure Grown by GSMBE
A novel structure Gao.51 Im.rsP/GaAs MISFET with an undoped Gao.slIno.*eP layer serving as the airbridge between active region and gate pad was first designed and fabricated. Wide and flat characteristics of gm and f max versus drain current or gate voltage were achieved. The device also showed a very high maximum current density (610 mA/mm) and a very high gate-to-drain breakdown voltage (25 V). Parasitic capacitances and leakage currents were minimized by the air- bridge gate structure and thus high f~ of 22 GHz and high f,,, of 40 GHz for 1 pm gate length devices were attained. To our knowledge, both were the best reported values for 1 pm gate GaAs channel FET's.
Coherent pulsed injection seeding of two gain-switched semiconductor lasers
High-power, narrow-spectrum, short pulses at a wavelength near 830 nm are needed for optical logic applications. The authors report the generation of two coherent trains of pulses by pulsed injection seeding of two gain-switched semiconductor lasers with one mode-locked master oscillator. The available power was doubled and both lasers emit in nearly identical spectral lines. Short pulses (30-50 ps) are generated at a repetition rate of 1.9 GHz. The spectrum is reduced to a single mode cluster and shows a 1.7 AA wide chirp suitable for pulse compression. The peak power is 0.1 W for each pulse train. The capability of this technique for coherent power combining is demonstrated.<<ETX>>