FORMATION OF CARBON FILMS AS THE SUBGATE DIELECTRIC OF GAAS MICROCIRCUITS ON SI-SUBSTRATES

Abstract

The technological aspects of the formation of thin α-C:H carbon films, the peculiarities of the ion-plasma Q-DLTS spectra of heterostructures α-C:H-Si and α-C: H-GaAs are considered, and activation energy, cross-trapping and density of deep traps, responsible for charge state, are determined. The correlation between the technological regimes of the α-C:H film formation and trap density is established. The technological methods and regimes that allow obtaining structures with a relatively small surface state density Nss≤1012 cm-2 are determined. This allows using these structures as a subgate dielectric in GaAs-CMOS structures of LSICs.

Low-temperature epitaxy of GaAs-layers on silicon substrates with the use of excimer lasers is developed, where germanium film acts as a buffer layer between Si and GaAs. The technology of carbon films formation by deposition from the carbon target is developed. The use of carbon films as a subgate dielectric allows the formation of CMOS-transistors on GaAs-epilayers with symmetric threshold voltages, which opens a new direction for the development of the sub-micron technology of LSICs and enables to increase the LSICs speed and reduce their production cost.