Paper Session I-C - Technology Advances and Developments in Low Power Gallium Arsenide for Space Applications

The evolution of gallium arsenide (GaAs) technology has developed to the point where it is quite suited for low power operation in space. The preliminary requirements for space-based integrated circuit applications are reviewed, and evidence that a GaAs technology known as complementary heterostructure field effect transistors (CHFETs) has proven to meet the demands of the space environment is presented. Further examples of how the complementary GaAs technology has demonstrated the potential for operation in the Gigahertz frequency range using power supply voltages at or below 2.5 Volts are presented. The analog and digital technological needs for space applications are identified and being met by complementary GaAs technologies when compared to commercial-off-the-shelf (COTS) electronics. Emphasis on the manufacturing costs of low power GaAs technologies when compared to those associated with COTS modified for space applications is addressed. Finally, information by both the Air Force and commercial sector concerning the need for low power GaAs technology insertion into future space-based systems is provided

Effects of carrier injection profile on low noise thin Al0.85Ga0.15As0.56Sb0.44 avalanche photodiodes

Avalanche photodiodes (APDs) with thin avalanche regions have shown low excess noise characteristics and high gain-bandwidth products, so they are suited for long-haul optical communications. In this work, we investigated how carrier injection profile affects the avalanche gain and excess noise factors of Al0.85Ga0.15As0.56Sb0.44 (lattice-matched to InP substrates) p-i-n and n-i-p diodes with total depletion widths of 145-240 nm. Different carrier injection profiles were achieved by using light with wavelengths of 420, 543 and 633nm. For p-i-n diodes, shorter wavelength light produces higher avalanche gains for a given reverse bias and lower excess noise factors at a given gain, compared to longer wavelength light. Thus, using 420 nm light on the p-i-n diodes, corresponding to pure electron injection conditions, gave the highest gain and lowest excess noise. In n-i-p diodes, pure hole injection yields significantly lower gain and higher excess noise, compared to mixed carrier injection. These show that the electron ionization coefficient, α, is higher than the hole ionization coefficient, β. Using pure electron injection, excess noise factor characteristics with effective ionization ratios, keff, of 0.08-0.1 were obtained. This is significantly lower than those of InP and In0.52Al0.48As, the commonly used avalanche materials combined with In0.53Ga0.47As absorber. The data reported in this paper is available from the ORDA digital repository (DOI: 10.15131/shef. DATA: 5787318)

\u27NCHIPSIM\u27-a microcomputer simulator of NMOS chip performance indicators

© 1991 IEEE. The authors have developed a computer simulator called \u27NCHIPSIM\u27 which can be used to simulate with a microcomputer the performance indicators of an integrated circuit microprocessor chip based on silicon NMOS technology. In addition to predicting the various chip performance indicators such as its size, power consumption, maximum clock frequency, computational capacity, functional throughput and the fabrication yield for a chip with given technology parameters, the simulator can also be used to simulate the dependence of any of the performance indicators based on the technology feature size as well as on the integration level of the chip

Charge Storage Effects in Pseudomorphic High Electron Mobility Transistors

We present for the first time results on charging effects in fully fabricated pseudomorphic high electron mobility transistors (PHEMTs), using in-situ, photoemission and conduction (PEC) studies. The experiments were performed on GaAs based FETs with strained InGaAs channels. These studies evaluate hole storage in the channel area which modifies the threshold voltage of the field effect transistors (FETs). Deep level transient spectroscopy (DLTS) measurements were performed and the results compared to the data obtain from the photo studies. Understanding of hole storage is of significance in modeling the devices since holes are attracted towards the channel when the device is pinched off