Toshihide Izumiya

Comparative study on carbon incorporation in MOCVD AlGaAs layers between arsine and tertiarybutylarsine

We have studied the carbon incorporation properties in MOCVD Al0.7Ga0.3As epilayers on differently oriented surfaces by using either arsine or tertiarybutylarsine (TBAs). The present study has shown that the carbon incorporation in the layers using TBAs is significantly lower than that using AsH3 under higher VIII ratio and/or lower temperature conditions. The results also indicate that the carbon does not originate in TBAs but in TMG and TMA. According to these results, the carbon incorporation mechanism is discussed through analysis of reaction products by growth. A growth model in which As molecules rather than H atoms act on the carbon elimination from the growth surface is presented.

New magnesium doping source for metalorganic chemical vapor deposition: Octamethyldialuminummonomagnesium

Octamethyldialuminummonomagnesium (an adduct of trimethylaluminum and dimethylmagnesium) is proposed as an alternative candidate for an Mg doping source in metalorganic chemical vapor deposition. Water cooling for the reactor wall was important to prevent predecomposition of the adduct. Almost flat doping profiles were obtained independent of Mg concentration. Long doping tails were not observed. The doping efficiency was independent of substrate temperature between 600 and 700 °C, indicating a lower decomposition temperature for this Mg source. It was suggested that carrier concentration control can be improved by removing Si containing impurities from this Mg source.

The deep levels in InGaAlP epilayers grown by metalorganic chemical vapor deposition using tertiarybutylphosphine

InGaAlP epilayers and double-hetero structure light emitting diodes (LEDs) were grown by metalorganic chemical vapor deposition (MOCVD) using tertiarybutylphosphine (TBP). The photoluminescence (PL) intensities were low compared with the epilayer grown using PH 3 , and depended markedly on the TBP synthesis lots. Deep levels, were studied and two oxygen related levels were observed in the epilayers with small PL intensities. An intimate relation between the deep levels and the photoluminescence (PL) intensity has been found. A larger TBP flow rate reduced the deep level concentrations and improved the PL intensity

Magnesium doping using an adduct of trimethylaluminum and dimethylmagnesium in metalorganic chemical vapor deposition

Abstract Mg doping for metalorganic chemical vapor deposition of Ga 1− x Al x As, using octamethyldialuminummonomagnesium (an adduct of trimethylaluminum and dimethylmagnesium), was studied as a function of Al composition and growth conditions. The Mg incorporation efficiency increased with decreasing growth temperature, and the maximum concentration was as high as 2.3 × 10 20 cm -3 at a growth temperature of 700°C for GaAs. An increase in Mg incorporation efficiency was seen with increasing Al composition, suggesting less Mg re-evaporation from the growing surface for layers with higher Al compositions. The limiting maximum attainable concentration values seemed to reach the same value, independent of Al composition. Long doping transients, as reported in the literature, were not observed. The doping response was essentially unchanged independent of Al composition.