| 摘要 |
In a process for the epitaxial growth on a crystal base of semi-conductor crystals by reduction or decomposition of a gaseous compound at an elevated temperature the temperature of the crystal growth surface is reduced when an initial layer has been deposited. Silicon or germanium P+type substrates (27) (drawing not shown) containing 1 ppm boron or silicon N+ type substrates containing 0.05 ppm phosphorus trichloride are placed on a graphite heater (17) in a quartz vessel (11) and first heated in pure hydrogen to remove oxides, &c. then heated in feed gas containing by volume 99% hydrogen, 1% Si Cl4 or Ge Cl4 and 0.05 ppm phosphorus trichloride or diborane as dopant. When a layer at least 0.1 micron thick has been deposited, the temperature is reduced and if desired the feed gas flow rate and concetration may be varied. The substrate temperature sensed by an optical pyrometer may be automatically controlled. Deposition of gallium phosphide on gallium arsenide from feed gas containing Ga Cl3 P Cl3 and a trace of barium dopant is referred to.ALSO:In a process for the epitaxial growth on a crystal base of semi-conductor crystals by reduction or decomposition of a gaseous compound at an elevated temperature the temperature of the crystal growth surface is reduced after an initial layer has been deposited. Silicon or germanium P + type substrates (27) (Drawing not shown) containing 1 p.p.m. boron or silicon N + type substrates containing 0.05 p.p.m. phosphorus trichloride are placed on a graphite heater (17) in a quartz vessel (11) and first heated in pure hydrogen to remove oxides &c. then in feed gas containing by volume 99% hydrogen, 1% SiCl4 or GeCl4 and 0.05 p.p.m. phosphorus trichloride or diborane as dopant. When a layer at least 0.1 micron thick has been deposited, the temperature is reduced and, if desired, the feed gas flow rate and concentration may be varied. The substrate temperature sensed by an optical pyrometer may be automatically controlled. Si substrates are heated in pure hydrogen to 1300 DEG C. and then in feed gas at about 1300 DEG C. the temperature being reduced to 1295-1000 DEG C. Ge substrates are heated in feed gas at 825 DEG C. and this is reduced to 600 DEG C. or 675 DEG C. N on N + and P on P + epitaxial layer substrate devices may be formed and a P-N junction may be made by depositing a P layer on to an existing N on N + device or an N layer on to a P layer and such junctions used as a Zener or varactor diode. Deposition of gallium phosphide on gallium arsenide from feed gas containing GaCl3, PCl3 and a trace of barium dopant is referred to.
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