Reliable ICs fabricated using a production GaAs HBT process for military and commercial applications

Abstract

Reliability performance of a complex malog integrated circuit (IC) f a b r i d using a producton GaAslAlGaAs HetcmjI" Bipolar Transistor (HBT) process technology is i e p t d . Three temperature constant stress lifetest projects a median-time-to€dare of 5200 years for a monolithic five-stage logarithmic amplifier operating at a 125°C junction temperature. This techaology is currently delivering both s p x q d & d ctass"K" ICs to major government programs and high-volume, lowICs for commercial applications. In addition to reliabiity performance, the advantages of HBTs for anaIog/"wave and digital functions in cozlllnunication systems =highlighted. INTRO"Today's state-of-the-art performance in communication systems has been achieved largely due to advances in III-V. semiconductor technology including GaAsIAlGaAs Heterojunction Bipolar Transistor (Hl3T) process technology. GaAs HBT has been demonstrated to have inherent advantages in performance over its silicon counteqarts, GaAs MESFET and HENlT technologies [1,2]. GaAs HBTs have found insertion into spacddefense applications and moie recently, high-volume, low-cost commercial applications such as wireless communication. With GaAs HBT becoming the preferred technology for use in system enhancement and next generation system design, demonstration of a reliable technology is a key factor that establishes TRWs production GaAs HBT process as a mature technology for providing reliable, high-performance integrated circuits (ICs) at low cost and high yield to both the spaddefense and commercial markets. This paper briefly describes TRw's production GaAs HBT process technology, device characteristics, circuit application and IC refia6ility. Ail electrical and reliability performance discussed in this paper is based strictly on devices and ICs fabricated using this production process. PROCESS TECHNOLOGY AND PRODUCTIONTRWs standard GaAdMGaAs HBT production process features Npn GaAs/AIGaAs HBT devices grown on semi-insulating GaAs substrates by solid source molecular epitaxy (MBE). The HBT device features include: 1400A lx1019 c~n -~ The process uses a seWidigrad base ohmic metas (SABM) fabrication process hat aligns the baseebmiccontactto theemittermesaedge Theemitterand~mesa~€onnedby w e t etch, and boron implantaton provides device isohtion. AuBelpdlAu, AuGe?NilTilAu and r e h t o r y T i i h meahaon Wt-ensedfor the base, CxdkcW and&molnnic contact, respectively. Figure 1 shows a scamkg eleolh-on microscopy (!EM) photo of Npn HBT devices other key process features include sdmitky diodes, PIN &des. 1 w s q Nicr thin film l-e&ors pF€Q, m 3 d -h s d a -d (MIM) capacitws, multiple h&ix"ct levels, backside g " d vias and Siticon nitride (SW glassivation. In this pmxss technology, schottky and PIN diodes can be integrad w i d HBTs without added process complexity due b the common MBE material profile sbared between dese device structures.All wafezs are subjected to in-process SCheeIljng that includes process control monitor testing for process c~n f w , 48-hour unbiased seabiliz...

Estimating the transit time of an Al<inf>y</inf>Ga<inf>1&#x2212;y</inf>As HBT in the Gaussian doped base region for low to moderately high level of injection

“…This technology is also being used to develop electronics for space applications because of its excellent analog and radio frequency (RF) performance over an extremely wide range of temperatures [2]. On the other hand, HBT process technology is reported to be used in the fabrication of large number of complex analog integrated circuits for commercial and military applications [3].…”