The observed initial gain degradation of AlGaAs/GaAs heterojunction bipolar transistors under current stress was investigated. The change in device characteristics is attributed to a dissociation of passivating hydrogen in the base layer during stress. The hydrogen passivation occurs during the implant isolation process. An activation energy of 0.75 eV was measured for the junction temperature dependence of the dissociation process.

We describe a low fabrication cost, high-performance implementation of SiGe BiCMOS on SOL The use of high-energy implant allows the simultaneous formation of the subcollector and an additional n-type region below the buried oxide. The combination of buried oxide layer and floating n-type region underneath results in a very low collector-to-substrate capacitance. We also show that this process option achieves a much lower thermal resistance than using SOI with deep trench isolation, both reducing cost and curbing self-heating effects.

We will discuss the operating principles, design, fabrication and measured properties of an inductively coupled monolithic spiral transformer Devices like this one can be integrated into module substrates, and are practical for RF wireless applications operating at frequencies above several hundred MHz. The common model for a transformer is a pair of mutually coupled inductors. At high frequencies, however, capacitive coupling between the windings leads to non-ideal behavior and resonance, limiting the device's useful operating range. We show that the wide-band characteristics of transformers is closely related to that of coupled transmission lines, and we can rake advantage of this feature to obtain good transformer behavior at higher resonant modes.

The realization of collector-up light-emitting complementary charge injection transistors is reported. The devices have been implemented in molecular-beam-epitaxy-grown n-InGaAs/ InAlAs/p-InGaAs and n-InGaAs/InP/p-InGaAs heterostructures using a self-aligned process for the collector stripe definition. Electrons, injected over the wide-gap heterostructure barrier (InAlAs or InP) by the real-space transfer (RST) process, luminesce in the low-doped p-type InGaAs active layer. An essential feature of present devices, besides their self-aligned collector-up configuration, is a relatively heavy doping of the n-type emitter channel, with the sheet dopant concentration of 4X 1012 cmn2. This ensures a higher uniformity of the electric field in the channel and provides a relief from RST instabilities at a high level of collector current (linear density 10 A/cm). Devices with InAlAs and InP barriers show rather different optical characteristics, mainly due to the different band lineups hEc/AE, in InGaAs/InAlAs and InGaAs/InP heterostructures, leading to different ratios between the RST current and the parasitic leakage of holes from the collector into the channel. At high RST current densities, the effective carrier temperature T, in the active collector layer, determined from the high-energy tails of the luminescence spectra, is strongly enhanced compared to the lattice temperature. This decreases the device radiative efficiency and leads to a thermionic emission of carriers out of the active layer.

It has recently become evident (Davis et al, 1998) that there are many important design and performance advantages to be gained by using a flip-chip silicon-on-silicon MCM (multichip module) architecture for RF applications. This paper describes the structure and assembly of a 1.016 GHz GSM MCM transceiver. In this example, an RF transceiver chip is flip-chip mounted on a circuited silicon substrate which, as part of its circuitry, includes embedded capacitors, inductors and resistors. The resulting flip-chip silicon-on-silicon structure, which is called a “tile” and incorporates all of the RF sensitive nodes, is itself inverted and solder connected to the top side circuitry on a double sided FR-4 laminate substrate. This substrate is furnished with bottom side solder balls for surface mount assembly to, for example, an FR-4 PWB motherboard. Tests of the resulting MCM package showed an exceptionally clean RF resonance peak with none of the spurious resonance peaks that were observed with a transceiver chip of the very same design when enclosed in a conventional leaded package and surface mount soldered to a conventional PWB motherboard. This compact packaging architecture allows for the design and manufacture of optimized MCM packages for RF transceivers that can be as thin as the MCM tile alone

We show an example design of a cellular telephone that demonstrates the marked contrast between passive component usage in its base-band and radio sections. We discuss the performance demands that applications like these place on passive components and how these demands relate to the technology used to build the components. Recently, we have demonstrated and reported on the use of silicon-on-silicon thin film modules to integrate the tank resonator circuit of the 1 GHz UHF VCO in a GSM transceiver. We discuss some of the ways that these results can be extended to take further advantage of component integration. A unique characteristic of modules used in RF applications is the integration of thin-film spiral inductors. One of the concerns in the tight integration of these components is crosstalk arising from mutual inductive coupling between components. We have calculated the mutual inductive coupling between spiral inductors, with and without ground planes, and present representative examples from typical module designs

We report an integrated VCO in a GSM transceiver with less than 1% frequency error in the first design and spurious-free frequency response. The first-design success with high accuracy is due to considering the package as part of the circuit design and included in optimization. The spurious-free frequency response is achieved by carefully designing a high-Q (37.5 at 1 GHz) inductor and a co-planar stripline in the VCO resonator.

A charge injection transistor, which operates as an exclusive-OR logic gate, and a monolithic multiterminal de- vice, electrically reprogrammable between OR and NAND logic function, have been successfully implemented in a Si/Sio 7Geo 3 heterostructure grown by rapid thermal epitaxy on a Si substrate. Room temperature operation of the charge injection transistor is demonstrated, with 10 dB odoff ratio for the excluAive-OR logic function. Microwave measurements indicate a short circuit current gain cutoff of 6 GHz, for a device with a source-drain dis- tance of 0.5 wm. Device simulations were used to identify primary dependencies of the device performance on the parameters used in the design of the structure. Further structural improvements are suggested. I. INTRODUCTION N important direction in microelectronics research is A the development of new functional devices, which can perform logic tasks that would normally require an assembly of several transistors ( 11. The physical operation of these new functional devices is generally different from the field-effect principle, that CMOS logic devices use, or from the potential- effect principle of bipolar transistors. The phenomenon of real-space transfer' (RST) offers interesting opportunities for building functional devices. The concept of RST describes the process in which carriers in a narrow semiconductor layer, accelerated by an electric field parallel to the layer, acquire high-average energy and then spill over an energy barrier into the adjacent layer. This principle underlies the operation of a three terminal heterojunction device, called the charge injection transistor (CHINT) (3). A generic CHINT structure is illustrated in Fig. 1. One of the two conducting layers, the emitter, plays the role of a hot- cathode, with the heating voltage applied between the contacts S and D. The other conducting layer, the collector, is separated by a heterostructure barrier. The RST manifests itself with the increase of the collector current IC, at constant collector bias Vc, when a sufficient high-heating bias Vo is applied. A fundamental property of the CHINT is the symmetry equivalence (4) between the internal states S(VD, VC) of the

We have built 10 and 26 GHz differential VCOs using InP HBTs. Both oscillators use a 3 stage emitter coupled pair ring section. The 10 GHz VCO is connected in the well known fashion but the 26 GHz circuit uses a patented summed output from each of the three ECP (Emitter Coupled Pair) stages. The circuits are powered from a single 5 V supply consuming 250 mW. The chip size is 870/spl times/975 /spl mu/m/sup 2/. The phase noise at a 100 kHz offset for the 10 and 26 GHz oscillators is 83 dBc/Hz and -70 dBc/Hz respectively.

An extraction technique for determining the small-signal equivalent circuit model of an InP/GaInAs heterojunction bipolar transistor is presented. The equivalent circuit includes the extrinsic base collector capacitance and extrinsic base resistance, It is clearly indicated which elements are uniquely determined, and which elements are estimated.

A strained InGaP/GaAs/InGaAs multiquantum well laser has been monolithically integrated with GaAs metal–semiconductor field effect transistors (MESFETs) in a differential pair configuration to form a transmitter circuit. The structure utilized a single epitaxial growth step in which the laser was grown on top of the MESFET. The circuits operated with bandwidths as high as 4 GHz.

We present results on optoelectronic integrated circuits in both the GaAs and InP systems. The GaAs transmitters employed GaAs MESFETs integrated with an MQW-SCH ridge laser. These circuits operated with a bandwidth of 3.5 GHz. The GaAs receivers consisted of a p-i-n photodiode integrated with a GaAs MESFET in a simple single stage preamplifier configuration. The circuits exhibited gains of 17 dB and bandwidths of 4 GHz. The InP receivers employed an InGaAs/InAlAs photodiode integrated with a pseudomorphic MODFET. These circuits exhibited bandwidths as high as 10 GHz and sensitivities of -31.8 dBm, -26 dBm and -17 dBm at 1, 2 and 10 Gb/s, respectively.

Monolithic PIN-FET photoreceivers were investigated in both the InP and GaAs systems. The GaAs-based circuits consist of a single growth step in which the p-i-n diode was grown on top of the MESFET. The circuits exhibit flatband gains as high as 17 dB and bandwidths of 2.0 GHz. The InP circuits feature regrown MODFETs integrated with p-i-n diodes. These devices exhibit a gain of 17 dB and a bandwidth of 10 GHz

Charge injection transistors and logic elements have been successfully implemented in a Si/Si/sub 0.7/Ge/sub 0.3/ heterostructure grown by rapid thermal epitaxy on a Si substrate. Shallow p+ source and drain ohmic contacts are obtained by a boron diffusion from a selectively deposited boron doped Ge layer. Room temperature operation of the charge injection transistor is demonstrated for the first time. High frequency measurements indicate a short circuit current gain cutoff frequency of 6 GHz.<>

Recent progress in the growth and processing of InP-based heterostructures has led to the design of heterojunction bipolar transistors (HBTs) with typical cutoff frequencies in excess of 100 GHz and current gains of 50-100. Besides the high frequency performance, the noise properties of the devices are significant for their use in mixers, local oscillators or amplifiers. Extensive studies of noise in AlGaAs/GaAs HBTs have been reported, which suggest that the low frequency noise is often dominated by generation-recombination type of noise due to traps in GaAs. Measurements on InP/InGaAs HBTs have shown lower noise as compared to AlGaAs/GaAs HBTs and evidence for recombination noise due to shallow traps. We present here experimental results on the frequency dependence of noise in InP/InGaAs HBTs from 0.1 Hz to 1 MHz. The purpose of this work is to identify the significant noise sources and to determine their dependence on external biasing conditions

Charge injection transistors have been implemented in molecular beam epitaxy grown InGaAs/InAlAs/InGaAs and InGaAs/InP/InGaAs heterostructures using a self-aligned process for the collector stripe definition. Scattering parameters have been measured in the frequency range from 100 MHz to 40 GHz. InP barrier devices show the best microwave performance ever reported for a real-space transfer transistor: at 40 GHz the short circuit current gain mod h21 mod is 8 dB and the power gain is larger than unity. The slope of mod h21(f) mod depends on the bias point and is generally gentler than 20 dB decade-1. Extrapolating at the measured slope, we find mod h21 mod =1 at f=115 GHz. The short circuit current gain cut-off fT, defined by extrapolation at 20 dB decade-1 from the point of least mean square deviation of the measured slope from 20 dB decade-1, is fT=73 GHz. Devices with InA/As barriers show a relatively slower performance (fT=32 GHz). The difference is discussed in terms of the relative rates of intervalley scattering and real-space transfer in the two heterostructures.

The monolithic integration of optical and electronic components on the same substrate permits higher speed and more stable operation of the systems that they comprise. Optoelectronic integrated circuits (OEICs) are the objects of intense research, and many improvements in their performance have been reported in the literature in both the InP and GaAs systems. Of particular interest have been monolithic photoreceivers and optical transmitters. We present data on the successful operation of both integrated-optical receivers and transmitters suitable for use in wide-bandwidth optical transmission systems.

The high frequency performance of InP/Ga0.47In0.53As heterojunction bipolar transistors (HBTs) with a varying base thickness was measured. The diffusion constant of minority carrier electrons in the heavily doped base was found to be 105 cm2/s. It is demonstrated that the short base transit times in fast InP/Ga0.47In0.53As HBTs is mainly due to the high value of the diffusion constant of thermalized electrons. The contribution of hot electron ballistic transport is relatively small.

A single-stage integrating front-end photoreceiver linear array of eight elements comprised of a P-I-N In0.53Ga0.47As photodiode integrated with a selectively regrown pseudomorphic In0.65Ga0.55AsIn0.52Al0.48As MODFET by using molecular-beam epitaxial (MBE) regrowth was investigated. Cutoff frequencies of the 1.0-µm regrown MODFET were ft = 24 GHz and = 50 GHz. Transconductance of the regrown MODFET's were as high as 495 mS/mm with a current density (Ids) of 250 mA/mm. The 3-dB bandwidth of the photoreceiver was measured to be 1 GHz. The bit-rate sensitivity at 1 Gbit/s was -29.5 dBm for a BER of 10−9 with l.55-µm excitation, which is more than 4-dB greater sensitivity than that of other single-stage OEIC photoreceivers and within 1-2 dB of the best multiple-stage OEIC photoreceivers. The single-stage amplifier exhibited as much as 25 dB of flat- band photocurrent gain.

Optoelectronic S-parameter measurements offer the bandwidth needed to characterize today's state-of-the-art transistors, but have not yet achieved the throughput or accuracy provided by a vector network analyzer with microwave probes. In this paper, we discuss a new approach in which movable optoelectronic probes, calibrated by testing simple standard devices, are stepped around the wafer to provide accurate, high-throughput S-parameter measurements. Sub-picosecond laser pulses drive photoconductive switches on the probe tips, to generate electrical stimulus pulses and define sampling intervals, and signals are transferred to and from the wafer under test by coplanar waveguide transmission lines and plated contact bumps. The probes provide electrical pulses as short as 3 psec (FWHM), while maintaining a broadband 50 ohm termination to ensure stability of the device under test. Since probe flexure under contact significantly disturbs alignment of free-space beams, fiber-optic input is used to improve reproducibility. Analysis by vector error correction in the frequency domain removes systematic errors and separates the incident and reflected pulses without subjective time-window gating. We have demonstrated precise measurement of the complex reflection coefficient S 11 at frequencies up to 175 GHz. Noise simulations have been performed to investigate the effect of various system parameters on the measurement uncertainty and useful bandwidth for S-parameter tests