ABSTRACT Space and other DoD systems require high reliability components, which will survive a long mission life. Heterojunction Bipolar Transistors (HBT’s) are key components in these systems. NGST has developed a robust system for long term testing of HBT’s at very high current densities (200-300 kA/cm). This test measures current enhanced degradation that may not appear with standard high temperature reliability screening methods. The system is fully automated providing high current stress, with periodic comprehensive in-situ testing of all devices.

A selective molecular beam epitaxy (MBE) regrowth approach is presented and applied in the demonstration of complementary InP heterojunction bipolar transistor (HBT) technology for monolithic integration of NPN and PNP HBTs. State-of-art performance has been observed: The DC gain was 35 for both integrated NPN and PNP HBTs. f(T) of 79.6 GHz and f(max) of 109 GHz were achieved for NPN devices while f(T) of 11.6 GHz and f(max) of 22.6 GHz were achieved for PNP devices. Little performance degradation has been observed compared with same design NPN or PNP HBT layers grown on individual substrates, Monolithic microwave integrated circuits (MMICs) based on complementary In-P HBT technology have been studied for the first time using this technology and their electrical characteristics are presented.

An InP-based integrated HBT amplifier with PNP active load was demonstrated for the first time using complementary HBT technology (CRBT). Selective molecular beam epitaxy (MBE) regrowth was employed and a merged processing technology was developed for the monolithic integration of InP-based NPN and PNP HBTs on the same chip. The availability of PNP devices allowed design of high gain amplifiers with low power supply voltage. The measured amplifier with PNP HBT active load achieved a voltage gain of 100 with a power supply (V/sub CC/) of 1.5 V. The corresponding voltage swing was 0.9 V to 0.2 V. The amplifier also demonstrated S/sub 21/ of 7.8 dB with an associated S/sub 11/ and S/sub 22/ of -9.5 dB and -8.1 dB, respectively, at 10 GHz.

A Ka-band oscillator has been designed, fabricated and tested using InAlAs/InGaAs HBTs. Coplanar waveguide technology has been employed to improve the Q-factor of the circuit. An output power of 2.6 dBm with DC to RF conversion efficiency of 7.8% was measured at 31.7 GHz. Low phase noise of −87 and −112 dBc/Hz were achieved at an offset frequency of 100 kHz and 1 MHz respectively. These low phase noise values can be attributed to the low 1/f noise of the InAlAs/InGaAs HBT devices and the coplanar design used for the circuit.

In this work, monolithic integration of NPN and PNP InAlAs/InGaAs complementary HBTs was demonstrated using a regrowth approach by MBE. The integrated HBTs showed little degradation over similar discrete devices. The DC gain was 35 for both integrated NPN and PNP HBTs. f/sub T/ of 79.6 GHz and f/sub max/ of 109 GHz were achieved for NPN devices while f/sub T/ of 11.6 GHz and f/sub max/ of 22.6 GHz were achieved for PNP devices.

The power performance of InP based single HBTs has been mediocre compared with their double HBTs counterparts due to their inherently low breakdown voltage. For power amplifiers requiring moderate output power levels, single HBTs are more cost effective due to their simplicity of fabrication and design. InP-based single HBTs have demonstrated power performance at 10 GHz of 1.37 mW//spl mu/m/sup 2/, 11 dB gain and 33.9% power-added-efficiency. In this work, a graded InAlAs/InGaAs emitter base junction and a low-doped thick collector was employed to lower the turn-on voltage and increase the breakdown voltage respectively. InAlAs/InGaAs single HBTs were subsequently fabricated with undercut collectors for reduced base-collector capacitance. A 4-finger 2/spl times/10 /spl mu/m/sup 2/ HBT unit cell exhibited 22.5 dBm continuous wave (CW) output power (2.23 mW//spl mu/m/sup 2/ power density), 35% power-added-efficiency and an associated gain of 10.5 dB at 10 GHz. To our knowledge, this is the best output power density performance for InP based single HBTs.

Broad band amplifiers with two Darlington feedback topologies, namely resistive biased and mirror biased, have been designed, fabricated and characterized. The HBT layers used for amplifiers were grown by MBE. To reduce the knee voltage and increase the breakdown voltage of the devices, graded base-emitter junction and low-doped, thick collector have been employed. The fabricated amplifiers have achieved 10.95 dB gain with 25.5 GHz bandwidth at DC power consumption of only 34.7 mW. State-of-art Gain-Bandwidth-Products per dc power were achieved for both amplifiers (/spl ges/2.60 GHz/mW). The fabricated amplifiers also demonstrated moderate output power (8.3 dBm) at 10 GHz with a low DC power consumption of only 40 mW.