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Differential capacitance measurements on Schottky barrier contacts are used to determine deep energy levels for 29 different impurities implanted into silicon. Back-ground doping and deep levels are separated by making use of the sharply peaked implantation distribution. Donor or acceptor behavior is identified by the shape of the measured apparent charge profile. Energy levels measured for many impurities after annealing of the radiation damage agree with values known from literature. Other levels are caused by a non-thermal state of incorporation into the silicon lattice, e.g. for C, Si, and Ge, even after annealing of the radiation damage. Some impurities, e.g. Nb, Ni, Ti, and Na, show more than one state of incorporation, concentrations of which vary with the annealing conditions. Many implanted elements, especially those having a low solubility, e.g. Au, Be, Co, Se, etc., show strong out-diffusion and precipitation at the surface at annealing temperatures around 500°C. [ABSTRACT FROM AUTHOR]

Dislocations in VPE GaP grown on (100) oriented LEC GaP substrates have been characterized, and their origins and effects on LED performance have been investigated. In non-nitrogen doped epilayers, the dislocations are found to originate in the substrate and propagate through the epilayers in straight lines in [100] and <211> directions. The dislocation density of the epilayer is found to be nearly equal to that of the substrate. Introduction of nitrogen during growth of the epilayer has been observed to bend these so-called 'inclined≓ dislocations propagating through the layer into [0−1 1] directions in the (100) plane and thus produces segments of [0 −1 1] dislocations to relieve the lattice parameter mismatch due to N. The mismatch dislocation density is observed to be proportional to the N doping level. At very high N doping levels, > 10 cm, a large number of new inclined dislocations are observed, which may be in part due to GaN precipitation. The effects of dislocations on LED properties were investigated by measuring dislocation densities in the individual diodes using the electron beam induced current mode of the SEM and comparing this with the spot brightness and luminous flux. The dislocations were observed to produce dark spots in the EL emission in many cases. For a series of runs where all growth and processing parameters were fixed, a good correlation between B/J and dislocation density was observed with B/J decreasing with increasing dislocation density in the range < 1 × 10 cm to 1 × 10 cm. [ABSTRACT FROM AUTHOR]

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Single crystal layers of ZnS and ZnSe have been expitaxially grown on p-type GaP using an HCl close-spaced vapor transport system. Grown layer doping is accomplished using heavily doped source (ZnS, ZnSe) material and a zinc vapor diffusion process that reduces the number of compensating zinc vacancies. Experimental characteristics of nZnS-pGaP and nZnSe-pGaP diodes indicate dominance of the forward I-U relationship by space-charge-limited flow in the 10-10 ohm-cm ZnS and ZnSe. The reverse I-U characteristics of these devices agree qualitatively with a multistep tunnelling process but show larger than expected reverse currents. The reverse bias capacitance is strongly frequency dependent in all devices studied. Forward injection electroluminescence was not observed from any of the nZnS-pGaP and nZnSe-pGaP devices studied. [ABSTRACT FROM AUTHOR]

This paper describes gallium arsenide varactor diodes which develop effective values of f over 130 GHZ and will operate in double-diode parametric amplifiers at idler frequencies up to 43 GHZ. With such diodes it is possible to build wide band amplifiers which give good low noise performance without refrigeration. For example, an uncooled two-stage amplifier with a bandwidth of 500 MHZ at 26 dB gain gives an overall excess noise temperature at 7-25 GHZ of 85degreesK of which only 60degreesK is due to the varactor.
In recent years low noise parametric amplifiers which combine wide band-widths with high stability have been developed at S.E.R.L. for certain radar and satellite communication receivers. These amplifiers (Gittins et al. 1968) used the Pearson double-diode idler circuit (Pearson and Lunt 1964) as the cornerstone of the design, but the wide bandwidths were achieved by an innovation in which an extra resonant circuit of variable Q is coupled into the Pearson idler loop. Low noise temperature was obtained by cooling the diodes to liquid nitrogen temperature or below. However, refrigeration is unacceptable for many systems and, in particular, requirements at X-band now call for amplifiers with an excess noise temperature below 100degreesK when operating at ambient temperature. This sort of performance needs an idler frequency of at least 40 GHZ and an effective diode quality factor (f) greater than 100 GHZ. This paper describes the design and construction of new diodes which have such characteristics. [ABSTRACT FROM AUTHOR]