T. Block

High performance, high yield InP DHBT production process for 40 Gbps applications

High-speed digital logic is essential in diverse applications such as optical communication, frequency synthesizers, and analog-digital conversion. Current research efforts indicate that technologies utilizing heterojunction bipolar transistors (HBTs) are the preferred approach for systems operating at clock frequencies of 40 GHz and above. This need for higher performance electronics for space and defense applications has driven the development of InP HBTs at TRW. Consistent and continuous improvements from the baseline MBE structure and process technology have enhanced frequency performance, breakdown voltage, producibility, yield, reliability such that InP HBTs are being used successfully for many commercial, space, and defense applications. This paper describes our optimized high-yield production InP DHBT process which simultaneously combines f/sub T/>170 GHz, f/sub max/>190 GHz, and breakdown voltage /spl sim/7 V.

Reliability investigation of 0.07-μm InGaAs-InAlAs-InP HEMT MMICs with pseudomorphic In 0.75 Ga 0.25 As channel

The authors have investigated the reliability performance of G-band (183 GHz) monolithic microwave integrated circuit (MMIC) amplifiers fabricated using 0.07-/spl mu/m T-gate InGaAs-InAlAs-InP HEMTs with pseudomorphic In/sub 0.75/Ga/sub 0.25/As channel on 3-in wafers. Life test was performed at two temperatures (T/sub 1/ = 200 /spl deg/C and T/sub 2/ = 215 /spl deg/C), and the amplifiers were stressed at V/sub ds/ of 1 V and I/sub ds/ of 250 mA/mm in a N/sub 2/ ambient. The activation energy is as high as 1.7 eV, achieving a projected median-time-to-failure (MTTF) /spl ap/ 2 /spl times/ 10/sup 6/ h at a junction temperature of 125 /spl deg/C. MTTF was determined by 2-temperature constant current stress using /spl Delta/G/sub mp/ = -20% as the failure criteria. The difference of reliability performance between 0.07-/spl mu/m InGaAs-InAlAs-InP HEMT MMICs with pseudomorphic In/sub 0.75/Ga/sub 0.25/As channel and 0.1-/spl mu/m InGaAs-InAlAs-InP HEMT MMICs with In/sub 0.6/Ga/sub 0.4/As channel is also discussed. The achieved high-reliability result demonstrates a robust 0.07-/spl mu/m pseudomorphic InGaAs-InAlAs-InP HEMT MMICs production technology for G-band applications.

Degradation mechanism and reliability improvement of InGaAs/InAlAs/InP HEMTs using new gate metal electrode technology

The degradation mechanism of 0.1 /spl mu/m InGaAs/InAlAs/InP HEMTs subjected to elevated temperature lifetest has been resolved with the techniques of scanning transmission microscope (STEM) and high-resolution energy-dispersive X-ray analysis (EDX). The results show that Schottky junction degradation is the dominant degradation mechanism, consisting of Ti inter-diffusion and In/sub 0.52/Al/sub 0.48/As Schottky barrier layer degradation. The degradation of the In/sub 0.52/Al/sub 0.48/As Schottky barrier exhibits the formation of TiAs/sub x/ and indium-rich In/sub 0.52+x/Al/sub 0.48/As and/or indium depleted In/sub 0.52-x/Al/sub 0.48/As under elevated temperature lifetest. The Schottky junction degradation mechanism can be alleviated by using a new gate metal electrode technology (NGMET), which exhibits superior reliability performance to that of the Ti/Pt/Au gate metal electrode. Moreover, InP HEMT MMICs using NGMET exhibit comparable RF performance to that of InP HEMT MMICs with Ti/Pt/Au gate metal. The results achieved here demonstrate the further enhancement of 0.1 /spl mu/m InP HEMT MMIC technology at Northrop Grumman Space Technology (NGST) using NGMET for military/space applications with high reliability performance requirement.

A 0.5 watt-40% PAE InP double heterojunction bipolar transistor K-band MMIC power amplifier

We report on the first InP DHBT K-band fully integrated power amplifier which achieves 0.5 Watts of output power and 40% power added efficiency (PAE). The power DHBTs obtain a BVceo >18 V and an f/sub T/ and f/sub max/ of 80 GHz and 160 GHz, respectively. The MMIC amplifier combines eight 1.5/spl times/30 /spl mu/m/sup 2/ emitter fingers for a total periphery of 360 /spl mu/m/sup 2/. At 21 GHz the MMIC power amplifier achieves a linear gain of 9.4 dB, output power of 27 dBm with a 40% PAE. The amplifier was operated under a Vce=5.5V and Jc=54 KA/cm/sup 2/ and obtained a corresponding power density of 1.4 mW//spl mu/m/sup 2/. To our knowledge this is the highest output power obtained for a fully monolithic-50-/spl Omega/-matched MMIC power amplifier based on InP HBT technology.

Tradeoff of DC/RF performance versus reliability in 0.1 /spl mu/m InP HEMTs

The tradeoff of DC/RF performance versus reliability has been explored on 0.1 /spl mu/m InP HEMTs. The tradeoff between performance and reliability shows the dependence on the process techniques. While higher performance could be achieved with certain process techniques, the reliability performance is adversely affected. Nevertheless, all the process variations explored here exhibit activation energy of approximately 1.9 eV. However, the time-to-failure (TTF) at lifetest temperatures of 230/spl deg/C and 250/spl deg/C and median-time-to-failure (MTTF) at junction temperature of 125/spl deg/C depend on the process techniques. The results are beneficial for balancing performance versus reliability through the adjustment of the processing technique.

The effect of gate metals on manufacturability of 0.1 μm metamorphic AlSb/InAs HEMTs for ultralow-power applications

Four types of gate metallization were investigated to evaluate the manufacturability of 0.1 mum AlSb/InAs HEMTs. It has been found that device performance strongly depends on the gate metallization. This information is essential for the manufacturability of 0.1 mum AlSb/InAs HEMTs for ultralow-power applications.

High Performance and High Reliability of 0.1 /spl mu/m InP HEMT MMIC Technology on 100 mm InP Substrates

Uniform millimeter wave 0.1 mum InP HEMT MMICs (Ka-band, Q-band, W-band, and distributed amplifiers) on 100 mm InP substrates have been demonstrated. Moreover, high performance and high reliability have been achieved. The results indicate that the readiness of 100 mm InP HEMT technology for insertion to support military/space applications.

First demonstration of monolithic InP-based HBT amplifier with PNP active load

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.

Gate Sinking Effect of 0. 1 μm InP HEMT MMICs Using Pt/Ti/Pt/Au

Gate sinking effect of 0.1 mum InAlAs/InGaAs/InP HEMT MMICs (with Pt/Ti/Pt/Au gate metals) subjected to elevated temperature lifetests has been investigated. The results show that Pt sinking is the dominant degradation mechanism caused by Pt diffusing into the In0.52Al0.4As Schottky barrier layer. Pt sinking explains the observed evolutions of Schottky diodes, Ids-Gm transfer characteristics, and the S21 increase. Scanning-transmission-electron-microscope micrographs substantiate the alleviation of Schottky junction degradation of InP HEMTs using Pt/Ti/Pt/Au gates. Moreover, 2-temperature lifetest shows that the activation energy is approximately 1.55 eV, based on a failure criterion of DeltaIDSS = -20%. The results from this study demonstrate that Pt sinking is the primary degradation mechanism of 0.1 mum InP HEMT MMICs with Pt/Ti/Pt/Au gate metals

A Ka-band monolithic low phase noise coplanar waveguide oscillator using InAlAs/InGaAs HBT☆

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. 2002 Elsevier Science Ltd. All rights reserved.