| 摘要 |
1515571 Vacuum depositing semi-conductors MATSUSHITA ELECTRIC INDUSTRIAL CO Ltd 19 May 1975 [23 May 1974 7 June 1974 (2)] 21146/75 Heading C7F [Also in Division H1] In molecular beam epitaxial deposition of a compound semi-conductor the conductivity type or composition of a selected region 22 of the epitaxial layer is caused to differ from that of the remainder 21 of the layer by the selective heating, during deposition, of the region 22 by means of a beam 30 of concentrated energy such as an electron beam or laser beam. In one Example Ge-doped GaAs is epitaxially deposited on a GaAs substrate 2 using molecular beams from respective Ge and GaAs sources. Firstly a uniformly n type layer 20 is deposited on the pre-heated substrate 2 using no concentrated energy beam, but when the beam 30 is scanned across the region 22 during a second deposition stage the Ge deposited in the additionally heated region 22 becomes an acceptor (Ge being an amphoteric dopant in GaAs) and the resulting layer has a p type strip 22 in otherwise n type material 21. In another Example GaP and GaAs sources are used for the molecular beams to deposit a GaAs x P 1-x mixed crystal. When an area of the surface is selectively heated by a beam of concentrated energy the material depositing on the selected area contains a higher concentration of P (i.e. lower value of x) than elsewhere in the layer. An Al molecular beam may additionally be used in this example. Preferred apparatus, temperature conditions, &c., are disclosed for both Examples. |
