Growth and electronic properties of gallium arsenide and germanium metal insulator semiconductor structures

Abstract

The metal insulator semiconductor (MIS) structure is arguably the most technologically important type of solid in existence. The microelectronics revolution of the last thirty years is made possible largely due to the ability to realize extremely high quality metal/SiO$\sb2$/Si metal oxide semiconductor (MOS) structures. Unfortunately, silicon does not stand out in its ability to pass charge carriers with the highest speed. Significant improvements in the performance of many areas of electronics would result if another, high mobility semiconductor could be implemented into a high quality MIS structure.

In this thesis, MIS structures incorporating two high-mobility semiconductors, GaAs and Ge, are investigated. An in situ, plasma-enhanced chemical vapor deposition system has been constructed which allows deposition of Si-based insulators and group IV semiconductors on the pristine GaAs or Ge surface.

For the GaAs MIS system, a thin Si/Ge interlayer between the insulator and GaAs surface is found to improve the insulator/GaAs interface. This has allowed the realization of high transconductance GaAs metal insulator semiconductor field effect transistors (MISFETs).

For the Ge MIS system, the growth of Ge on GaAs at 250$\sp\circ$C while maintaining a low interface trap density at the insulator/Ge interface is shown to be possible. The high hole mobility of Ge and high electron mobility of GaAs suggest possible uses of this structure for high performance complementary metal insulator semiconductor (CMIS) applications.