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Extended abstract of a paper presented at Microscopy and Microanalysis 2012 in Phoenix, Arizona, USA, July 29 – August 2, 2012.

In conventional boundary element formulations, the singularities of the fundamental solution are usually located on the problem boundary. This leads to difficulties in evaluating solution quantities on or near the boundary. A method is presented for locating the singularities on an auxiliary boundary outside the problem domain and having this auxiliary boundary location determined automatically via a Galerkin criterion. This automatic generation of the auxiliary boundary results in a highly accurate, adaptive but non‐linear method. The number of singularities can be significantly reduced compared to conventional boundary element formulations which usually require the same number of singularities as the number of boundary elements used. The method is illustrated with three examples involving Laplace's equation in two dimensions. Excellent numerical results are obtained in all cases using only a few singularities.

Composite silicided source-drains are being developed to provide low-resistance shallow junctions for high performance fine-line circuits. The junctions are usually formed either by implantation and drive prior to silicide formation or else by implantation immediately after, followed by a heat cycle. This paper describes a novel approach for the fabrication of CoSi 2 /n+-p junctions (2 . 5 Ω/□ sheet resistance), wherein the junctions are doped by diffusion through the contact windows using the conventional "poly-plug" doping cycle [1], [2]. LPCVD poly-Si is deposited on windows to previously silicided gate and source-drain regions, and exposed to PBr 3 at an elevated temperature. Since the diffusivity of dopants in silicides is higher than in bulk Si, this step transports the P through the poly-Si via the windows laterally into the silicide, to form uniformly doped junction surrounds. This poly-Si doping scheme for junction fabrication eliminates an ion-implant step, provides an independent means of tailoring channel length, and can potentially result in low-resistance contacts even if the window etch step has punched through the silicide, Electrical characteristics of 1.25-µm gate-length ring oscillators are similar to those of circuits processed with the conventional As implant and drive. Transistor I-V 's and subthreshold behavior remain unaffected by the silicide doping process. Junction depth and leakage are sensitive functions of the poly-plug thermal cycle, with a 950°C 30-min drive resulting in 0.3-µm junctions. For a 1-µm design rule circuit layout, 30 to 45 min at 950°C is judged adequate.

In this paper the temperature dependence of latch-up in a VLSI CMOS technology is studied. Both steady-state and pulse-induced dynamic trigger characteristics are presented showing a marked increase in latch-up resistance with decreasing temperature; in particular, a latch-up free condition is met for several structures at temperatures ranging between 100 and 200 K. The results of measurements of parasitic bipolar parameters and shunting resistances at different temperatures are reported, and their values are related to latch-up characteristics.

Let A be an arbitrary n×n matrix, partitioned so that if A=[Aij], then all submatrices Aii are square. If x is a positive vector, it is well-known that G( x ) =∪ N i=1 G i ( x ) , where G i ( x ) = z ‖(zI − A ii ) −1 ‖ −1 ⩽ 1 x i ∑ j = 1 j ≠ i N `‖A ij ‖x j , contains all the eigenvalues of A. The purpose of this paper is to give a new definition of the concept of an isolated subregion of G(x). An algorithm is given for obtaining the best such isolated subregion in a certain sense, and examples are given to show that tighter bounds for some eigenvalues of A may be obtained than with previous algorithms. For ease of computation, each subregion Gi(x) is replaced by the union of circular disks centered at the eigenvalues of Aii.

Temperature dependence of propagation delay time and power-delay product in Si MOSFETs (fabricated using 1 μm X-ray lithography) has been measured using 19-stage ring oscillators. The delay time was found to decrease with lowering temperature. As a numerical example we found that a delay time of 30 ps at room temperature decreased to 22 and 18 ps at 77 and 4.2 K respectively, and increased to 38 at 400 K. The power showed a slight increase with decreasing temperature, while the power-delay product decreased. The decrease in the delay time has been explained in terms of increase in the electron drift velocity with decreasing temperature, as well as decrease in one component of the capacitive load, namely the source-drain junction capacitance, due to carrier freeze-out.

Electron-beam lithography with a novel multilevel resist structure together with two-dimensional process and device modeling and dry processing with reactive sputter etching have been employed to produce silicon-gate NMOS devices with micrometer and submicrometer channel lengths. Results for transistors and ring oscillators are reported.

The method of fundamental solutions is a form of indirect boundary integral equation method. Its distinctive feature is adaptivity, gained through the use of an auxiliary boundary that is chosen automatically by a least squares procedure. The paper demonstrates the application of the method to problems in potential flow. A further advantage of the method is that the velocity field can be computed easily and accurately by a direct evaluation procedure.

The differential cross sections have been studied as functions of angle and bombarding energies for the B10(t, p)B12 reactions leading to the ground, 0.95, 3.39 and 3.75 MeV states of B12; for the B10(t, d)B11 reactions leading to the ground and 2.14 MeV states of B11; and for the B10(t, α)Be9 reactions leading to the ground, 2.430 and 3.04 MeV states of Be9. The total cross sections for these reactions at 1.950 MeV were obtained by numerical integration of differential cross sections and are 6.4, 8.0, 6.8 and 5.6; 35 and 12, 24 and 10 mb, respectively. The differential cross sections for all groups exhibit very smooth energy dependences and the total cross sections appear to approach essentially constant values in the vicinity of the Coulomb barrier. The angular distributions of the ground state deuteron group have been fitted with plane wave calculations including stripping and heavy-particle stripping. The energy dependence of the angular distribution of the ground-state α-particle group suggests that the B10(t, α)Be9 reaction proceeds, to some extent, by a pickup interaction. Possible mechanisms for the other reactions are also discussed.

Pactamycin levels in serum or urine could be determined either by a tissue culture assay or the disc-plate assay using Bacillus subtilis. After intravenous administration, the antibiotic level in the sera of various animal species decreased rapidly, with complete disappearance of the activity within 30 min. This decrease was not attributable to inactivation by blood or irreversible binding by tissues. Excretion in urine accounted for less than 1 per cent of the total antibiotic injected. In vitro, pactamycin was degraded by liver slices of dog at the rate of 487 μg/hr per g liver slice. If the counterpart of the in vitro-system operates in vitro, then the rapid inactivation of pactamycin and low recoveries in vitro can be explained. Cancer patients treated with the drug also showed low blood levels and poor recovery from urine; however, patients suffering from extensive liver metastasis had higher blood levels and excreted more pactamycin than those with no liver involvement. This could be attributed to the inability of the metastatically involved liver to degrade the antibiotic and could account for the somewhat more violent reactions of these patients to the drug.

The absorption, excretion, and fate of orally administered chlorphenesin carbamate- 3 H have been studied in the dog. The drug was well absorbed, with about 67–79 percent of a single oral dose of 100 mg kg appearing in the urine within 48 hr and only 4–12 per cent in the feces. Approximately 81 per cent of the urine radioactivity was present in neutral metabolites or their conjugates while 19 per cent of the radioactivity appeared as free or conjugated acidic metabolites. The major urinary metabolite in the dog, accounting for 59 per cent of the radioactivity in 0–12 hr and 32 per cent of the radioactivity in 12–48 hr, was a glucuronide of chlorphenesin carbamate. An additional 25 per cent of the radioactivity in urine was accounted for as the free drug or its sulfate conjugate. The major acidic metabolites in dog urine were p -chlorophenol, p -chlorophenoxylactic acid, and p -chlorophenoxyacetic acid. Several additional minor acidic and neutral metabolites also were isolated and characterized.

Toxicopathologic characterizations of two recently reported monamine oxidase inhibitors, α-methyl- and α-ethyltryptamine, were presented; the data included acute (mouse, rat) and subacute (rat, dog) toxicity evaluations. In the 28-day rat studies, α-methyltryptamine and α-ethyltryptamine were well tolerated at levels of 3 and 10 mg/kg, respectively. At higher doses, increasing retardation of body weight gains and signs of CNS stimulation occurred. The bioclinical data and pathologic findings indicated no drug related alterations in groups of dogs which received doses of 1, 3, and 10 mg/kg of α-methyltryptamine; one dog of the 10 mg/kg group lost a significant amount of weight during the month study. Dogs which received 30 mg/kg became acutely intoxicated but rapidly developed adaptive tolerance during 1 week of dosage. Daily doses of 3, 10, and 30 mg/kg of α-ethyltryptamine produced no clinical or histologic evidence of untoward drug effect in dogs during a 28-day period. After dosage of 90 mg/kg, three dogs showed signs of CNS stimulation; the livers of two of these dogs were severely congested. In these animal studies, α-ethyltryptamine has been found to be tolerated appreciably better than α-methyltryptamine It also should be noted that doses of α-ethyltryptamine which were well tolerated orally by the rat and the dog during subacute studies were thirty- to fiftyfold greater than the anticipated human therapeutic dose. In further studies, α-ethyltryptamine appeared to be without significant cardiovascular toxicity in the dog. The musculoirritant property in the rabbit was essentially nil at 1 mg/kg and moderate at 10 mg/kg. Daily oral doses of 10 mg/kg produced no effect on rat reproduction.

A new method for experimentally deriving the source-and-drain resistance of MOS transistors is presented along with experimental results verifying its accuracy. The method also yields the mobility reduction with high gate-oxide field. The measurements are done on two (or more) MOS transistors which are identical except that their gate lengths differ by a known amount.

We present results on very high-speed low-power devices and circuits fabricated using a NMOS technology scaled to submicron dimensions. These results illustrate the electrical behavior of single minimum-size devices, and present the performance of several submicron circuits, such as ring oscillators, a 3-GHz divide-by-two counter and a 90- MHz 16 × 16 multiplier.

Pulsed operation of Ge avalanche diodes has produced oscillations with efficiencies exceeding 40 percent at frequencies of 2-3 GHz. Computer simulation of diode and circuit behavior has provided an explanation for the observed results.

We present new experimental results on optimally scaled MOSFETs with channel lengths below 0.25 µm. These devices have been fabricated using a modified NMOS process. All patterns have been defined by direct-beam writing using both positive and negative electron resists. The gate oxide thickness of 80A together with properly adjusted ion implantation steps yields device thresholds of 0.5 V. All heat treatments have been kept as short as possible to ensure very shallow source-drain junctions. All contact structures are scaled to 1 × 1 µm window features. Finished devices show excellent performance. Long-channel-like behavior is preserved for supply voltages below 2.5 V. The subthreshold slope is 88 mV/decade. Current drive capabilities are the highest ever reported for silicon MOSFETs. The devices exhibit outstanding transconductance values between 270 and 300 mS/mm.

A CMOS process is described that is designed to optimize the transistor characteristics of the n-channel and p-channel devices simultaneously. This is achieved by making the n- and p-channel devices symmetric in channel doping, junction depths, sheet resistivities and threshold voltages. The resulting devices have CoSi 2 source/drains with sheet resistivities of 1.5-2 Ω/square, n+ and p+ polysilicon/TaSi 2 gate structures, Threshold voltages of 0.4 V and 1.5 µm separation between active to tub-edge regions. Diode characteristics of the CoSi 2 /n+ and CoSi 2 /P+ are determined to be as good as non-silicided silicon junctions. Maintaining the proper doping for the connected n+ and p+ polysilicon/silicide gates is demonstrated. Ring oscillator delays of 110 ps at 3.5 V are observed for devices with 0.5 µm channel lengths. The ring oscillator circuits are still operational at power supply voltages of 1.0 V due to the low threshold voltage of the transistors.

The recent extension of copyright protection in two directions is examined. One court decision held that in addition to the literal code, copyright may protect the structure, sequence, or organization of a program. Also, several cases have protected the general 'concept and feel' of the user interface. These decisions are discussed, as are other cases that are coming up. The uncertainty regarding the extent of the protection that remains, because the relevant cases are not particularly helpful guides for predicting how future cases will be decided, is considered. >

We have fabricated very high speed, low power devices and circuits using a submicron NMOS technology. Our results illustrate the electrical behavior of single minimum size devices, and present the performance of several submicron circuits, such as ring oscillators, a 3 GHz divide-by-two counter and a 90 MHz 16 × 16 multiplier.

We report on measurements and computer simulations for enhancement and depletion MOSFETs with submicron channel lengths as small as 0.2 µm. The behavior of the devices is analyzed using both advanced techniques such as transmission electron microscopy for profile measurements and numerical models to simulate processing conditions and device behavior in two dimensions.

5-(α,α,α-Trifluoro- m -tolyoxymethyl)-2-oxazolidinethione, or U-11,634, effectively inhibits pregnancy in rats at multiple oral or subcutaneous doses of 2.5 mg or a single subcutaneous dose of 5 mg. A toxicologic evaluation of this compound was performed at multiples of this therapeutic dose. The acute LD 50 studies were done intraperitoneally in the mouse (451 mg/kg) and orally in the rat (524 mg/kg). Significant signs of toxicity were not observed in swine photosensitization studies or in rat fetal studies. Rats tolerated an oral dose of 10 mg/kg/day for one month without significant untoward effect; however, higher levels (30 and 100 mg/kg/day) produced various effects, the most significant of which was an antithyroid effect. When U-11,634 was given orally to dogs for one month, it was slightly toxic at 30 mg/kg/day, moderately toxic at 100 mg/kg, and very toxic at 300 mg/kg/day. The signs of toxicity consisted of antithyroid effects in all the treated dogs, and toxic hepatitis in some of the dogs at the higher dosages. Additional studies in dogs and rats at 100 mg/kg/day indicated that the antithyroid effects in both species, and elevated bromsulfalein retention and alkaline phosphatase values in dogs reversed following cessation of treatment. The increase in monocytes in the blood and the bone marrow changes need further study. The antifertility effects of U-11,634 in rats were evaluated in the presence of exogenous thyroxine and iodine. This supplemental treatment did not change the pregnancy-inhibiting activity of U-11,634 nor did it inhibit pregnancy in the absence of U-11,634. The effect on early pregnancy of subacute treatment with known antithyroid agents was assessed. No inhibition of pregnancy was observed following their administration from proestrus through day 6 of pregnancy. On the basis of these observations and available literature reports, it is concluded that the antithyroid effect of U-11,634 does not account for the compound's antifertility efficacy.

The differential cross sections were studied as functions of angle and bombarding energies for the B/sup 10/(t,p)B/sup 12/ reactions leading to the ground and 0.95-, 3.39-, and 3.75-Mev states of B/sup 12/; for the B/sup 10/ (t,d)B/sup 11/ reactions leading to the ground and 2.14-Mev states of B/sup 11/; and for the B/sup 10/(t, alpha )Be/sup 9/ reactions leading to the ground and 2.430- and 3.04-Mev states of Beg. The total cross sections for these reactions at 1.950 Mev were obtained by numerical integration of differential cross sections and are 6.4, 8.0, 6.8, and 5.6; 35 and 16; and 12, 24, and 10 mb, respectively. The differential cross sections for all groups exhibit very smooth energy dependences and the total cross sections appear to approach essentially constant values in the vicinity of Coulomb barrier. The angular distributions of the ground state deuteron group were fitted with plane wave calculations including stripping and heavy-particle stripping. The energy dependence of the angular distribution of the groundstate alpha -particle group suggests that the B/sup 10/(t, alpha )Be/sup 9/ reaction proceeds, to some extent, by a pickup interaction. Possible mechanisms for the other reactions are also discussed. 28 references. (auth)

The theory for bipolar transistors operated at high collector currents is weak. Controversy exists as to when (or if) lateral current spreading dominates over the Kirk effect. This paper attempts to answer this question. The output characteristics of silicon bipolar transistors in the common emitter configuration are analyzed in detail. The analysis proceeds by extracting the values of transistor generation current (due to small amounts of collector multiplication) from experiment, fitting these values to a model which accounts for the modulation of the collector depletion layer by mobile space charge and the lateral spreading of collector current. It is found that a continuous and gradual increase in collector effective area occurs as the collector current increases. In this manner the deleterious effects of high current density are moderated. By accounting for this effect, cut-off frequency calculations are brought into good agreement with experiment. As an independent check on the validity of the analysis, electron ionization rates are obtained, which are in good agreement with values in the literature. Effects associated with emitter crowding are also shown to be unimportant in the structures investigated.

The effects of thermal feedback on the characteristics of multiple emitter stripe silicon power transistors are considered in detail and 1) a method is presented for correlating the isothermal characteristics with the effects of thermal feedback so that observed output characteristics may be predicted and 2) emitter stripe designs are developed to achieve uniform temperature and power distributions. A number of authors have considered the effects of nonuniform temperature distribution. This paper will present a method of isothermal characterization of collector current and base-emitter voltage as functions of power density and temperature, which when combined with two-dimensional thermal analysis for proposed designs, allows the prediction of steady-state device characteristics. The specific temperature uniformity required to alleviate thermal feedback can be predicted and achieved by optimizing the thermal coupling between emitter stripes.

This letter reports the first CW operation of silicon TRAPATT diodes in the microwave region. In particular, CW operation of silicon diodes, using room temperature heat sinking, has been obtained from 2.5 to 4.0 GHz. The maximum power output achieved thus far has been 3.0 watts and the maximum efficiency has been 20 percent.

The MOSFET with doubly diffused drain has been proposed as a solution to the problem of degradation in small MOSFETs. We find good agreement between measured gate current and values calculated assuming that the gate current is due to hot channel electrons thermionically emitted into the gate oxide.

A simple piecewise-linear analysis method which can be used to predict the logic propagation delay (/spl tau//SUB d/) for fine-line Si NMOS logic gates is presented. The set of equations derived shows explicitly the dependence of /spl tau//SUB d/ on inverter noise margins, driver transconductance, load current, node capacitance, driver and load input conductances, and driving waveshapes. Submicron-channel Si NMOS has demonstrated a /spl tau//SUB d/ as low as 30 ps for unity fan-in and fan-out ring oscillators. It is shown that the p-n junction capacitances of the driver and load devices account for up to 50% of the total logic gate capacitances. If reduced (as in SOI for example), Si NMOS logic gates might produce a /spl tau//SUB d/ as low as 15-20 ps. The delay analysis can be used to predict the operation of larger circuits. An example using a flip-flop frequency divider is given.

Pulsed operation of germanium IMPATT diodes has produced oscillations from 10 MHz to 12 GHz, with efficiencies exceeding 40 percent for frequencies between 2 and 3 GHz. Recorded waveforms show that IMPATT oscillations are required to initiate the lower frequency high-efficiency modes. The diodes are epitaxial diffused junction n-p-p+mesa structures, with depletion widths ∼ 5 microns and breakdown voltages ∼ 60 volts. Typical diode area is 2 \times 10^{-4} cm2. Static I-V curves, obtained with circuit conditions which do not permit any oscillations, exhibit positive incremental resistance. The usual IMPATT mode would be expected to be between 6 and 12 GHz. Operation at frequencies below the IMPATT frequency requires circuit conditions suitable for IMPATT oscillations to be present to initiate the lower frequency, higher efficiency mode. This mode is characterized by a sudden decrease in diode voltage and a simultaneous increase in current, similar to that reported for silicon devices [1]. Reproducible current and Voltage waveforms have been recorded for four distinctly different low-frequency modes of operation which result only from changes in the ac circuit seen by the diode.

Silicon diode microwave oscillators and amplifiers employing two different diode structures are reported. These diodes employ the avalanche transit-time properties originally discussed by Read. A simple p-n junction has produced 13 mW of CW power at 10.5 Gc/s with 0.5 percent efficiency as an oscillator. A similar diode, when incorporated into a circulator coupled amplifier circuit, produced 30 Mc/s bandwidth with 20 dB of gain. Noise figures in the 50 to 60 dB range were obtained in preliminary measurements. Experimental results with these diodes are shown to be in qualitative agreement with the small-signal theory of Misawa. A double diffused "hyperabrupt" diode has also been fabricated as prescribed by Read. These diodes have produced 19 mW of CW power at 5 Gc/s with 1.4 percent efficiency and 13 mW with 1.5 percent efficiency.