Joseph Richard

Effects of the silicon-to-carbon ratio and the hydrogen content in amorphous SiC thin films prepared by reactive sputtering☆

Abstract Amorphous silicon carbide thin films were prepared with a wide range of composition by reactive sputtering. Rutherford backscattering and nuclear reaction analysis were used to determine the silicon, carbon and hydrogen contents in the films. The optical properties were found to depend on both the silicon-to-carbon ratio and the hydrogen content. As in amorphous silicon, it was possible to obtain a Schottky barrier between a metal (in this case gold) and amorphous silicon carbide.

Al/Al2O3/InP MIS structures

Metal‐insulator‐semiconductor (MIS) structures were produced by electron‐beam deposition of Al2O3 on InP. The electrical properties of such structures were investigated. For optimum conditions, capacitance/voltage (C/V) measurements show that the interface state density can be reduced to 1011 states cm−2 eV−1 by heat treatments. Capacitance transient measurements lead to an estimate of 2×103 cm sec−1 for the surface recombination velocity.

Very simple a-Si:H TFT fabrication process for LCD-TV application

Abstract Amorphous silicon based thin film transistors for the driving of liquid crystal displays have been fabricated in a very simple way with only 2 photolithographic steps. The process for TFT and matrix elaboration are explained. The transistor electrical characteristics are shown to be compatible with LCD working conditions.

Nuclear reaction analysis of hydrogen in amorphous silicon and silicon carbide films

Abstract The 1 H( 11 B, α)αα nuclear reaction is used to determine the H content and the density of amorphous semiconductor Si 1− x C x H z and SiH z thin films. Rutherford backscattering is used to determined the x values and infrared transmission to study the hydrogen bonds. We have observed a transfer or/and a release of hydrogen under bombardment by various ions and we show that this last effect must be taken into account for a correct determination of the hydrogen content. An attempt is made to correlate the hydrogen release with electronic and nuclear energy losses.

Density of states in thin film transistors from the modulated photocurrent technique: application to the study of metastabilities

Abstract We demonstrate the possibility of probing the density of states (DOS) of the active a-Si:H layer of Thin Film Transistors (TFT) by means of the modulated photocurrent technique. The DOS deduced from this technique on Top Nitride TFTs is compared with values deduced from the subthreshold slopes of the transfer characteristics. We also study the consequences of gate bias stresses on the TFTs. For gate bias stresses up to ±30V, we observe a shift in the transfer characteristics along the gate voltage axis, but did not measure any significant change in the DOS above midgap. These results are discussed and compared with those recently published in the literature by other authors.