F.M. Yamada

A 108-GHz InP-HBT monolithic push-push VCO with low phase noise and wide tuning bandwidth

This paper reports on what is believed to be the highest frequency bipolar voltage-controlled oscillator (VCO) monolithic microwave integrated circuit (MMIC) so far reported. The W-band VCO is based on a push-push oscillator topology, which employs InP HBT technology with peak f/sub T/s and f/sub max/s of 75 and 200 GHz, respectively. The W-band VCO produces a maximum oscillating frequency of 108 GHz and delivers an output power of +0.92 dBm into 50 /spl Omega/. The VCO also obtains a tuning bandwidth of 2.73 GHz or 2.6% using a monolithic varactor. A phase noise of -88 dBc/Hz and -109 dBc/Hz is achieved at 1- and 10-MHz offsets, respectively, and is believed to be the lowest phase noise reported for a monolithic W-band VCO. The push-push VCO design approach demonstrated in this work enables higher VCO frequency operation, lower noise performance, and smaller size, which is attractive for millimeter-wave frequency source applications.

High-reliability GaAs-AlGaAs HBTs by MBE with Be base doping and InGaAs emitter contacts

The authors have developed a modified MBE growth process to produce high-gain n-p-n GaAs-AlGaAs heterojunction bipolar transistors (HBTs) with a mean time to failure (MTTF) of 1.5*10/sup 8/ h at 125 degrees C. Beryllium incorporation and diffusion are controlled through a combination of reduced substrate temperature and increased As/Ga flux ratio during MBE growth, resulting in extremely stable HBT profiles. The authors also demonstrate graded InGaAs surface layers with nonalloyed refractory metal contacts that significantly improve ohmic reliability compared to alloyed AuGe contacts. The ability to produce robust HBTs by MBE is critically important to this technology.<<ETX>>

ESD sensitivity study of various diode protection circuits implemented in a production 1 /spl mu/m GaAs HBT technology

Advanced GaAs Heterojunction Bipolar Transistors (HBTs) featuring smaller junction areas have an increased susceptibility to damage from Electrostatic Discharge (ESD) events and this is a topic of concern. In this paper, we examined the ESD sensitivity of various on-chip ESD-protection networks designed using base-collector (BC) junction diodes and Schottky diodes from a production 1 /spl mu/m GaAs/AIGaAs HBT process. The purpose of this work was to measure and evaluate the ESD sensitivity of various protection networks and determine their effectiveness as protection devices.

Reliability performance of components and ICs from a production 1 /spl mu/m GaAs HBT process

We report on the reliability performance of our advanced production 1 /spl mu/m GaAs/AlGaAs Heterojunction Bipolar Transistor (HBT) technology featuring HBTs with thinner Be-doped base layer, smaller emitter dimensions and higher current density (Jc) operation than our current production process. Reliability characteristics of discrete Npn HBTs, Schottky diodes, NiCr thin-film resistors (TFRs), trimmable CerMet TFRs and a HBT integrated circuit (IC) are presented. The purpose of this work was to qualify a new process technology for space/defense and commercial applications. The intent of this paper is to report the robustness of Be-doped HBTs at higher Jc operation and the high level of reliability achieved in an IC fabricated using this new process. Additionally, this paper provides a reference on reliability of passive IC components with compositional features similar to that commonly implemented in industry.

Reliability of a high performance monolithic IC fabricated using a production GaAs/AlGaAs HBT process

We report the worlds first lifetest results of a monolithic integrated circuit fabricated using GaAs/AlGaAs Heterojunction Bipolar Transistor (HBT) technology. The Successive Detection Logarithmic Amplifier (SDLA) was used as the standard evaluation circuit (SEC) to evaluate the HBT process. Results of a three temperature constant stress lifetest projects a median-time-to-failure (MTF) of >10/sup 7/ hours at 125/spl deg/C junction temperature with an activation energy (Ea) of 1.4 eV and log-sigma (/spl sigma/) of 0.7. Failure criteria were based on RF and DC characteristics of the SDLA. Failure mode is also discussed. This study establishes GaAs/AlGaAs HBT technology as a mature and reliable process technology.

High-reliability GaAs HBT monolithic microwave amplifier

High-reliability performance of an X-band high-intercept MMIC amplifier fabricated using a production GaAs/AlGaAs HBT process technology is reported. Operating at 20 kA/cm/sup 2/ quiescent collector current density, the single-stage balanced amplifier with on-chip regulation has a projected median-time-to-failure (MTF) of 4/spl times/10/sup 7/ hours at a 125/spl deg/C junction temperature. MTF was determined by three-temperature constant-stress accelerated lifetest using |/spl Delta/S21|>1.0 dB as the failure criterion. Additionally, an activation energy (Ea) of 1.2 eV and log-standard deviation (/spl sigma/) of 0.7 was measured. This is the first report of HBT reliability based on small-signal microwave characteristics of HBT MMIC amplifiers under lifetest.