P Clauws

Study of electrical damage in GaAs induced by SiCl4 reactive ion etching

In the last decade reactive ion etching has become a very important tool for the patterning of submicron features. Although the particle energies involved in this etching process are relatively low, they still are high enough to alter the characteristics of semiconductor materials. In this paper we report on the electrical damage in n‐ and p‐type GaAs induced by SiCl4 reactive ion etching. We found that the etching process causes significant electrical damage extending hundreds of nm deep in the p‐GaAs but in n‐GaAs only minor changes are observed. The changes in p‐GaAs are thought to be due to the formation of EL2 point defects in a concentration comparable to the dopant concentration. Possible explanations for the observed differences in damage between p‐ and n‐type material are given.

Quantification of the low temperature infrared vibrational modes from interstitial oxygen in silicon.

Accurate conversion factors are obtained to determine the concentration of interstitial oxygen in silicon from the low temperature local vibrational mode absorption at 1136, 1128 and 1205 cm−1 for different resolutions and apodization functions. The absorption spectra at 6 K were fitted with fit functions in order to extract the amplitudes of interest in an accurate and reproducible manner. The ratio of the amplitude at room temperature to the low temperature amplitude then gives the conversion factors for 6 K. Based on a phonon model [H. Yamada-Kaneta Materials Science Forum, edited by G. Davies and M. H. Hazare (Trans Tech, Aveiro, 1997), 258–263, p. 355] and on occupation statistics the use of the conversion factors is extended to temperatures as high as 100 K, taking into account the broadening of the absorption peaks and the variation in the occupation of the different excited states.

A study of electrically active defects created in p-InP by CH4:H2 reactive ion etching

The electrical effects of reactive ion etching (RIE) of p-InP by CH4:H2 are investigated. By using optical deep-level transient spectroscopy, several deep-level defects could be detected. The main defect (E3) is found to be a donor with an energy level at Ec−0.38 eV. From depth profiles of both the net acceptor concentration and this defect, it follows that after RIE, the E3 defects are passivated by hydrogen. Simultaneous passivation of both acceptors and donors on p-InP is reported. Subsequent rapid thermal annealing at increasing temperatures shows that the E3 defects are first depassivated and then annealed out. The change of the Schottky barrier height with the anneal temperature could be explained by Fermi-level pinning due to E3 and depinning either by its passivation for low enough temperatures or by its annealing out at higher temperatures. Some possibilities concerning the physical nature of E3 are discussed.

Influence of SiCl4 Reactive Ion Etching on the Electrical Characteristics of GaAs

SiCl4‐RIE causes electrical damage to GaAs strongly related to doping type and level. Changes in C‐V and DLTS‐measurements can be related to EL2‐defects. Explanations for observed differences in n‐type and p‐type material will be presented.