Cora Salm

The Charge Plasma P-N Diode

A simulation study on a new rectifier concept is presented. This device basically consists of two gates with different workfunctions on top of a thin intrinsic or lowly doped silicon body. The workfunctions and layer thicknesses are chosen such that an electron plasma is formed on one side of the silicon body and a hole plasma on the other, i.e., a charge plasma p-n diode is formed in which no doping is required. Simulation results reveal a good rectifying behavior for well-chosen gate workfunctions and device dimensions. This concept could be applied for other semiconductor devices and materials as well in which doping is an issue.

Fabrication and Characterization of the Charge-Plasma Diode

We present a new lateral Schottky-based rectifier called the charge-plasma diode realized on ultrathin silicon-on-insulator. The device utilizes the workfunction difference between two metal contacts, palladium and erbium, and the silicon body. We demonstrate that the proposed device provides a low and constant reverse leakage-current density of about 1 fA/μm with ON/OFF current ratios of around 107 at 1-V forward bias and room temperature. In the forward mode, a current swing of 88 mV/dec is obtained, which is reduced to 68 mV/dec by back-gate biasing.

Low-Frequency Noise Phenomena in Switched MOSFETs

In small-area MOSFETs widely used in analog and RF circuit design, low-frequency (LF) noise behavior is increasingly dominated by single-electron effects. In this paper, the authors review the limitations of current compact noise models which do not model such single-electron effects. The authors present measurement results that illustrate typical LF noise behavior in small-area MOSFETs, and a model based on Shockley-Read-Hall statistics to explain the behavior. Finally, the authors treat practical examples that illustrate the relevance of these effects to analog circuit design. To the analog circuit designer, awareness of these single-electron noise phenomena is crucial if optimal circuits are to be designed, especially since the effects can aid in low-noise circuit design if used properly, while they may be detrimental to performance if inadvertently applied.

Structural and optical characterization of porous anodic aluminium oxide

Spectroscopic ellipsometry and scanning electron microscopy (SEM) experiments are employed to characterize porous aluminum oxide obtained by anodization of thin aluminum films. Rutherford backscattering spectra and x-ray diffraction experiments provide information on the composition and the structure of the samples. Results on our thin film samples with a well-defined geometry show that anodization of aluminum is reproducible and results in a porous aluminum oxide network with randomly distributed, but perfectly aligned cylindrical pores perpendicular to the substrate. The ellipsometry spectra are analyzed using an anisotropic optical model, partly based on the original work by Bruggeman. The model adequately describes the optical response of the anodized film in terms of three physically relevant parameters: the film thickness, the cylinder fraction, and the nanoporosity of the aluminum oxide matrix. Values of the first two quantities, obtained from fitting the spectra, are in perfect agreement with SEM results, when the nanoporosity of the aluminum oxide matrix is taken into account. The validity of our optical model was verified over a large range of cylinder fractions, by widening of the pores through chemical etching in phosphoric acid. While the cylinder fraction increases significantly with etch time and etchant concentration, the nanoporosity remains almost unchanged. Additionally, based on a simple model considering a linear etch rate, the concentration dependence of the etch rate was determined.

Gate-workfunction engineering using poly-(Si,Ge) for high-performance 0.18 /spl mu/m CMOS technology

We show that poly-SiGe can be readily integrated as a gate material into an existing CMOS technology to achieve significant increase in the transistor performance. In order to preserve the standard salicidation scheme, a buffer poly-Si layer is introduced in the gate stack. PMOST channel profiles are optimized to account for the change of the gate workfunction. High-performance CMOS 0.18 /spl mu/m devices are manufactured using p- and n-type poly-Si/Si/sub 0.8/Ge/sub 0.2/ gates.

The electrical conduction and dielectric strength of SU-8

This paper presents a study on the dielectric behavior of SU-8 photoresist. We present measurements on the leakage current levels through SU-8 layers of varying thickness. The leakage current is dominated by thermionic emission. We have further determined the dielectric strength of SU-8 to be 4.4 MV cm−1. The remarkably high dielectric strength allows the material to be used for high-voltage applications.

A Radiation Imaging Detector Made by Postprocessing a Standard CMOS Chip

An unpackaged microchip is used as the sensing element in a miniaturized gaseous proportional chamber. This letter reports on the fabrication and performance of a complete radiation imaging detector based on this principle. Our fabrication schemes are based on wafer-scale and chip-scale postprocessing. Compared to hybrid-assembled gaseous detectors, our microsystem shows superior alignment precision and energy resolution, and offers the capability to unambiguously reconstruct 3D radiation tracks on the spot.

Gate current and oxide reliability in p/sup +/ poly MOS capacitors with poly-Si and poly-Ge/sub 0.3/Si/sub 0.7/ gate material

Fowler-Nordheim (FN) tunnel current and oxide reliability of PRiLOS capacitors with a p/sup +/ polycrystalline silicon (poly-Si) and polycrystalline germanium-silicon (poly-Ge/sub 0.3/Si/sub 0.7/) gate on 5.6-nm thick gate oxides have been compared. It is shown that the FN current depends on the gate material and the bias polarity. The tunneling barrier heights, /spl phi//sub B/, have been determined from FN-plots. The larger barrier height for negative bias, compared to positive bias, suggests that electron injection takes place from the valence band of the gate. This barrier height for the GeSi gate is 0.4 eV lower than for the Si gate due to the higher valence band edge position. Charge-to-breakdown (Q/sub bd/) measurements show improved oxide reliability of the GeSi gate on of PMOS capacitors with 5.6 nm thick gate oxide. We confirm that workfunction engineering in deep submicron MOS technologies using poly-GeSi gates is possible without limiting effects of the gate currents and oxide reliability.

Constant and Switched Bias Low Frequency Noise in p-MOSFETs with Varying Gate Oxide Thickness

A scroll compressor having a housing, a fixed scroll stationary on said housing, an orbiting scroll nested with the fixed scroll and being mounted on the eccentric of the compressor crankshaft for orbital motion about the longitudinal axis of the compressor, the base of the orbiting scroll having an annular groove formed in the outside or low pressure side thereof, a passage formed through the base of the orbiting scroll and placing the groove in fluid communication with an intermediate section of the pressure continuum for providing an axial compliance force against the base of the orbiting scroll and urging the wrap tips thereof into sealing engagement with the adjacent base of the fixed scroll, an annular seal positioned in the groove and having an annular web provided with a substantially planar contact side positioned in sliding, sealing contact with a sealing surface of housing and having annular elastomeric sealing components slidingly sealed against the walls of the groove to provide an axial compliance pressure chamber which is sealed from ambient pressures.

Modeling of RTS noise in MOSFETs under steady-state and large-signal excitation

The behavior of RTS noise in MOSFETs under large-signal excitation is experimentally studied. Our measurements show a significant transient effect, in line with earlier reports. We present a new physical model to describe this transient behavior and to predict RTS noise in MOSFETs under large-signal excitation. With only three model parameters the behavior is well described, contrary to existing models.