| Budget Amount *help |
¥3,200,000 (Direct Cost: ¥3,200,000)
Fiscal Year 1991: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 1990: ¥2,400,000 (Direct Cost: ¥2,400,000)
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| Research Abstract |
The aim of this work is to achieve a carbon free MOMBE growth by removing the carbon from methyl radical the metalorganic precursors, such as TMG.The first trial was complete cracking of the methane (CH_4), but it was found that it is difficult, e13EA\ : specially in vacuum, because that the sticking probability of methane on the heater is too small. Next trial was a reverse way : removal of methyl radical from metal organic as methane using atomic hydrogen produced by a heated tungsten (W) filament13EA\ : . It seemed to be possible because TMG (Trimethy gallium) was seemed to be cracked to gallium gydride (gallan) and methane, when a small amount of TMG was passed through a heated tungsten filament of about 2000ﾟC.However, when the amount of TMG was13EA\ : increased one order of magnitude in order to grow GaAs, it was found that the W filament was broken due to a reaction with the cracked gallium.
Finally, it was confirmed that the best way is to use a new precursor, dimethyl amine gallan (GaH_3-NH(CH_3)_2--DMAG), which has no direct bond between Ga and C.the carbon concentration was reduced by about 5 orders of magnitudes : from 10^<20> c13EA\ : m^<-3> for the film grown with TMG to 1,2x10^<15> cm^<-3> for the film grown by DMAG at 550C.The carbon reduction was also confirmed by photoluminescence. The DMAG was stable for about 2 months as far as it was kept at about -10ﾟC.
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