We studied the selective epitaxy of GaAs grown by a technique called pulsed-jet epitaxy. Pulsed-jet epitaxy is a kind of atomic layer epitaxy (ALE) based on low-pressure metalorganic vapor-phase epitaxy (MOVPE). We compared growth behavior and layers grown by ALE and MOVPE. During ALE we supplied trimethylgallium (TMGa) and arsine (AsH3) alternately; however, during MOVPE we supplied TMGa and AsH3 simultaneously. At a growth temperature of 500, we obtained a better growth selectivity using ALE than using MOVPE. The lateral thickness profile of the ALE-grown GaAs layer at the edge of SiO2 mask was uniform. In contrast, the MOVPE growth rate was enhanced near the mask edge. Using ALE, we selectively grew GaAs epilayers even at mask openings with submicron widths. Scanning electron microscopy revealed that the ALE selectively grown structures had an uniform thickness profile, though the facets surrounding the structures depended on the orientation of mask stripes. After MOVPE, however, the (001) surface of the deposited layer was not flat because of the additional lateral diffusion of the growth species from the gas phase and/or the mask surface and some crystal facets. The experimental results show that, using ALE, we can control the shape of selectively grown structures. Selective epitaxy by ALE is a promising technique for fabricating low-dimensional quantum effect devices.

Isotope dilution secondary ion mass spectroscopy (ID-SIMS) using 30Si as a spike is investigated as a quantitative analysis method for trace amounts of Si. For a standard solution of Si, the relateve standard deviation of results using this method is 5% for 0.2 µg Si, and the determination lower limit is 18 ng. Using this method, the amount of Si deposited on the Ge(100) surface by the self-limited adsorption of SiH2Cl2 is determined to be about 1.00.2 monolayer.