Ron J. Pieper

A Unified Approach for Predicting Long- and Short-Term Capability Indices with Dependence on Manufacturing Target Bias

It is shown that the exact solution for the capability index (CPI) for Gaussian-distributed process with target bias can be expressed in terms of an unbiased CPI and a normalized target bias. The principal advantage of this specific formulation is that it facilitates evaluation of the degradation of the capability of the process due to bias between process mean and the process target. It is shown how this formalism, initially developed for the short-term process, is readily extended to long-term process for which the distribution is Gaussian. Readily isolated in the latter case are the two long-term CPI degrading effects, namely, process instability and target bias. Sufficient conditions to guarantee that long-term processes are distributed as Gaussian are discussed. Within the context of these assumed conditions, a new paradigm for a long-term locator ‘‘’’ is proposed. For a three sigma process the results indicate that the exact CPI model is a less pessimistic predictor than both of the industry CPI models tested.

Observations on frequency sensitivity of memristors

Comparison is made between established one dimensional linear and nonlinear memristor drift models with Hewlett Packard (HP) experimental data to test level of agreement. Models used in first phase of work are based on a sinusoidal applied voltage. Linear and nonlinear model data as well as HP experimental data were employed to make instantaneous power predictions during one full time cycle of the input waveform. Instantaneous power profile comparisons between both linear and nonlinear models for higher and lower frequencies with experimental data indicate that the power profiles are less sensitive to change in frequency though memristor hysteresis is highly sensitive. Model based simulation tests confirm that the frequency response scales inversely with an identified time constant based on physical properties and memristor dimensions.

Observations on Message Transmission Using Rossler and Lorenz Chaos Systems with PSpice and Matlab Models

Message transmission and reception systems (TRS) for both Lorenz coupled and Rossler coupled chaotic nonlinear systems are presented. Both a circuit simulator, PSpice, and a math package, Matlab, for predicting time evolution of coupled nonlinear differential equations were used. Both Matlab and PSPICE TRS models were set up, tested and demonstrated to yield essentially identical time evolution predictors. The Rossler TRS required a combination of the variable substitution method, typically employed for Lorenz TRSs along with the diffusive coupling technique, known to be necessary to couple two Rossler circuits. Examples indicating functionality of the systems to obscure and reliably recover messages for audio and sinusoid message types are presented.

A practical solution to the numerical butterfly effect in chaotic systems for fast but memory limited computers

The sensitive dependence on initial conditions found in nonlinear chaotic systems is known as the “butterfly effect”. Such systems when numerically analyzed can exhibit a convergence instability when employing standard numerical methods. Presented here is a practical numerical method for eliminating the “under-resolution” problem observed when solving for solutions to nonlinear chaotic systems with fast but memory limited computers. The proposed idea of using a micro-integrator loop was applied with the Modified Euler Method of numerical integration. The improvement offered by combining the micro-integrator loop with the classical integration scheme created an avenue for achieving convergence using much less memory than would be required if the micro-integrator loop was not employed.

Quasi-static modeling of an organic Schottky diode with trapped charge

The fundamental aspects of trap analysis in charge transport of organic semiconductors are reviewed by focusing on the role of traps in I-V characteristics of an organic Schottky diode. A p-type organic semiconductor based device is considered and the trap distribution is assumed to vary exponentially with energy. A numerical model is developed to determine the trapped charge concentration in the bulk region of organic semiconductor during the steady state trap free space charge limited current conduction. This model was used to deduce an analytical expression that relates the charge ratio θ with the Fermi level energy EF. This expression was utilized to determine the value of Fermi level energy EF corresponding to the charge ratio taken from the previously reported work based on an organic Schottky diode. Finally, the estimated value of Fermi level energy is applied to calculate the number of trapped charges through MATLAB based simulations. The concentration of trapped charges was found to be 1.54×1016 cm−3 which is in good agreement with the reported experimental results.

Simulation and transient analysis of organic/inorganic CMOS inverter circuit

Finite element device level simulations were used in conjunction with SPICE modeling to design and optimize a complementary MOS inverter circuit with an organic p-type and an inorganic n-type transistor combination. The device characteristics of the p-type and the n-type transistors were generated through 2D finite element device level simulations. The drain current (ID) vs. drain-source voltage (VD) and the drain current (ID) vs. gate voltage (VG) characteristics were modeled through fitting procedures to extract the SPICE parameters. Also, the design and transient analysis of a hybrid CMOS inverter circuit modeled using these SPICE parameters is presented. The inverter works reliably within the range of supply voltage (10V).

An Improved Characterization for Predicting a Capability index with Dependence on Manufacturing Target Bias

A target bias dependent capability index predictor is proposed and compared to two other commonly used paradigms. The formalism for the proposed approach assumes a normal (Gaussian) distribution in the values for a specified product parameter. A probabilistic description of the manufacturing process is used to predict the dependence for the fraction of rejected components on a short-term bias- independent capability index and a normalized target bias. Comparisons of paradigms for predicting both the fraction rejected and target bias dependent capability indices were tested for the special case of a three sigma process. The proposed capability index predictor can be implemented with either canned routines or with reasonably accurate analytic versions of the error function and its inverse. The demonstration indicates the proposed more accurate approach, is a less pessimistic predictor than the commonly used industry standards. Applicability of approach to formally include the impact of target bias on long-term capability index is discussed.

A transmission line model for analysis of thin film optical filters

In this paper, an analysis of thin film optical filters with a transmission line model is presented. This analogy is formalized through the transmission line telegraph equations. The predicted propagation phase rule drawn from this analogy is supported by a heuristic argument. A computer model based on transmission lines was developed to simulate various effects. The material presented here includes the optical equivalent of the anti-reflection quarter wave transformer, the application of Butterworth and Chebyshev tables for filter design, the optical tunneling effect, and replication of recently reported thin layer optical design results for angular spatial filtering

Memristor Drift Model based on conservation of mobile vacancies

A significant percentage of the analysis applied to memristors is based on the Linear Drift Model. In the Linear Drift Model the resistance of the doped region increases in direct proportion to the width of the doped region. It is shown that this is not consistent with the physical conservation of the mobile vacancies. A circuit model is proposed which is consistent with the conservation of the mobile vacancies and takes into account a high constant intrinsic resistivity indicative of the memristor “off state”. A numerical analysis (NA) scheme is tested and compared with reported Hewlett Packard memristor data and with the theoretical solution for the Linear Drift Model.

Modeling and characterization for polarization hysteresis of ferroelectric polymers

We present a modeling and simulation based study for the polarization hysteresis of ferroelectric polymers. A 2-dimensional finite element device-level model was implemented using SILVACOs ATLAS device simulator to generate the polarization hysteresis characteristics for the recently reported experimental data on Au/Poly(vinylidene fluoride-trifluoroethylene)/Au metal-insulator-metal (MIM) device. The simulated polarization dependence characteristics in the P(VDF-TrFE) thin-film were predicted from the parameters coercive field, remnant polarization and spontaneous polarization which were extracted from fitting to the experimental characteristics. The mathematical model which is referred by SILVACO for ATLASs ferroelectric model was implemented in MATLAB to generate the hysteresis curve. Landau-Devonshire expression for electric field in terms of polarization is also implemented in the MATLAB to produce the polarization hysteresis curve of mono-crystalline and polycrystalline ferroelectrics. The polarization hysteresis characteristics obtained from the ATLAS and MATLAB simulations were in good agreement with the reported experimental hysteresis characteristics.