Low Temperature Si/SiGe Epitaxy by UHV-CME and its Device Applications
博士 === 國立交通大學 === 電子工程學系 === 85 === Pure Si2H6 and GeH4 are used to grow Si and Si1-xGex epilayers at 550C by ultrahigh vacuum-chemical molecular epitaxy (UHV- CME). 0.1% B2H6 and 100 ppm PH3 diluted in H2 are used as the p- type and N-type dopant gases i...
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| Format: | Others |
| Language: | zh-TW |
| Published: |
1997
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| Online Access: | http://ndltd.ncl.edu.tw/handle/62305570247287365813 |
| Summary: | 博士 === 國立交通大學 === 電子工程學系 === 85 === Pure Si2H6 and GeH4 are used to grow Si and Si1-xGex epilayers
at 550C by ultrahigh vacuum-chemical molecular epitaxy (UHV-
CME). 0.1% B2H6 and 100 ppm PH3 diluted in H2 are used as the p-
type and N-type dopant gases in Si/Si1-xGex epitaxy. The Ge mole
fraction x and the growth rate of Si1-xGex epilayers show very
strong dependence oon the total source gas flow rate([GeH4]]+
[Si2H6]) and the source gas ratio ([GeH4]]/[GeH4]+[Si2H6]). The
results can be explained by the relationships of the source
fluxes, relative incorporation efficiency at activated surface
sites and hydrogen desorption under different growth conditions.
The boron concentration of Si1-xGex increases with increasing
GeH4 flow rate by keeping Si2H6 and B2H6 flow rates constant. It
may be due to the increase of the increase of the surface sites
which is caused by the increase of the hydrogen desorption rate
when a higher Ge mole fraction epilayer isgrown. The phosphorus
concentrations of Si and Si1-xGex show different behavior with
PH3 fluxat higher Ph3 flow rates while one increases linerly and
the other becomes saturated, respectively. These results can be
explained by a model based on the different levels of the
effects of phosphorus blocking of surface-activated sites
between Si and Si1-xGex epilayers. This effect can also be used
to explain the fact that a smaller decrease in the growth rates
of Si1-xGex epilayers occurs at a higher PH3 flow rate.
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