A NOVEL MONOLITHIC HBT-P-I-N-HEMT INTEGRATED-CIRCUIT WITH HBT ACTIVE FEEDBACK AND P-I-N-DIODE VARIABLE GAIN-CONTROL

We report the world's first functional MMIC circuit integrating HBT's, HEMT's, and vertical p-i-n diodes on a single III-V substrate, The 1- 10 GHz variable gain amplifier monolithically integrates HEMT, HBT, an d vertical p-i-n diode devices has been fabricated using selective MBE and a merged processing technology, The VGA offers low-noise figure, wideband gain performance, and good gain flatness over a wide gain con trol range, A noise figure below 4 dB was achieved using a HEMT transi stor for the amplifier stage and a wide bandwidth of 10 GHz, A nominal gain of 10 dB was achieved by incorporating HBT active feedback techn iques and 12 dB of gain control range was obtained using a vertical p- i-n diode as a varistor, all integrated into a compact 1.5 x 0.76 mm(2 ) MMIC, The capability of monolithically integrating HBT's, HEMT's, an d p-i-n's in a merged process will stimulate the development of new mo nolithic circuit techniques for achieving optimal performance as well as provide a foundation for high performance mixed-mode multifunctiona l MMIC chips.