Figures

Figure 1

The change of surface elemental population of a sapphire substrate during ECR plasma nitridation. The relative peak intensities are obtained by TOF-MSRI at different surface temperature.

Figure 2

The TOF-MSRI spectra vs. ECR-nitridation exposure time from a sapphire surface. The ECR power is 200 W and the substrate temperature is 700 °C.

Figure 3

TOF-MSRI spectra during a GaN buffer layer deposition. The neon scatter peak position shifts to lower time of flight due to the ECR plasma operation during the second, third and fourth spectra acquisitions.

Figure 4

Ga to N peak intensities measured by TOF-MSRI during GSMBE growth of GaN under varying ammonia gas pressure. The dotted curve is obtained for a Ga cell of 950 ° C. The solid curve is obtained for a Ga cell of 1000 °C. In both cases, the substrate temperature is 800 °C.

Figure 5

The correlation of optical properties of GSMBE GaN and Ga/N peak intensity ratio as measured by TOF-MSRI. PL band edge peak intensity (red triangles) and FWHM of PL signal (blue circles) at 10 K. A deviation is found for the sample containing oxygen as a contaminant by TOF-MSRI (marked by short arrows).

Figure 6

A TOF-MSRI spectrum from a sapphire substrate exposed to NH3+TEG at 550 °C. Only a small Ga peak is seen in the absence of N peak.

© 1998 The Materials Research Society