Characterization of in-situ Doped Polycrystalline Silicon Using Schottky Diodes and Admittance Spectroscopy

In this work, Schottky Au-Polycrystalline silicon diodes are successfully realised. The barrier height is around ФB = 0.74 eV as determined from Capacitance – Bias (C-V) characteristics. The depth profile of the apparent doping is deduced from these measurements. Its behaviour leads to the experimental profile. Moreover, the diode admittance measurements versus the frequency and the temperature at different biases show the possibility to use this device to characterise the electrical quality of the polycrystalline silicon

Erratum: ‘‘Picosecond large‐signal switching characteristics of a pseudomorphic AlGaAs/InGaAs modulation‐doped field‐effect transistor’’ [Appl. Phys. Lett. 61, 1187 (1992)]

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/70138/2/APPLAB-61-26-3194-1.pd

Picosecond large‐signal switching characteristics of a pseudomorphic AlGaAs/InGaAs modulated doped field effect transistor

We present the first comprehensive study of the large‐signal switching characteristics of an AlGaAs/InGaAs modulation‐doped field‐effect transistor on a picosecond time scale. Electro‐optic sampling is used to measure drain voltage response to a steplike gate input with a 2.8 ps rise time, at various dc biases. A large‐signal switching time of 6.2 ps is obtained. Features deleterious to high‐frequency device operation are observed, related to equivalent circuit parameters, and reduced by appropriate choice of operating point.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/69803/2/APPLAB-61-10-1187-1.pd

New large signal electrothermal HBT model with original parameters extraction procedure

A new large signal electrothermal Heterojunction Bipolar Transistor (HBT) model with original parameters extraction procedure is reported. The model, which is implemented in Hewlett-Packard MDS software, is based on a physical description and includes the high order effects of HBT operation. The extraction process requires only conventional DC and microwave measurements and does not need any numerical optimisations. In order to demonstrate the accuracy of the model, simulations performed without convergence problems are compared to measurements data for a 2x30um2 GaInP/GaAS HBT

New method for determining parasitic access inductances of high frequency on-wafer coplanar heterojunction bipolar transistors

New analytical extraction procedure is developed for determining independently the parasitic inductances of high frequency on-wafer coplanar Heterojunction Bipolar Transistor. It takes into account the influence of inductive effect due to other device parameters which can not be neglected for these transistors and it does not require any numerical optimizations or special test structures. In particular the analytical expressions demonstrate that base resistance and intrinsic and extrinsic base-collector capacitances have a significant effect on the accurate determination of the HBT parasitic inductances. Our theoretical investigations are validated using two types of transistors: A on-wafer coplanar GalnP/GaAs HBT and a microstrip mounted GalnP/GaAs which have a unity current gain cutoff frequency of 80 GHz respectively

Microstructure and opto-electrical properties of SnO2:In2O3 alloys thin films prepared by ultrasonic spray .

International audienceIn this work, we study the effect of indium weight ratio in solution: R = [In/Sn] on the properties of SnO2:In2O3 thin films prepared by ultrasonic spray method at fixed temperature of 300°C. The used precursors are tin chloride dehydrate and indium trichloride dissolved in methanol. To prepare hybrid SnO2:In2O3 thin films with different concentrations, the ratio R is varied in the range of 10–95 wt%. The resulting films were characterised by X-ray diffraction, scanning electron microscopy analysis, UV-visible spectrophotometer and conductivity measurement. The XRD results indicate segregation between SnO2 and In2O3 phases in all films. The optical transmittance is in the range of [75–85]%. The conductivity values of pure oxides are very low [~10–3 (Ω.cm)–1] and it is increased with R ratio until a maximum value of 1.2 × 102 (Ω.cm)–1 obtained at R = 95 wt%. Consequently, the higher figure of merit (Fm = σ.T.d) is obtained at this later ratio