| 摘要 |
1,186,340. Semi-conductor devices. STANDARD TELEPHONES & CABLES Ltd. 11 July, 1968, No. 33042/68. Heading H1K. At some stage during the manufacture of a semi-conductor device in a single crystal of semi-conductor material, the crystal comprises an unsupported plate thinned to less than 20 Á thickness. Such a plate is flexible, and as such is less easily broken than a thicker plate. The thin Si plate 2a illustrated originally formed part of an epitaxial layer on a thicker substrate, into which a B-doped region 3 was diffused to provide a PN junction. The substrate and, if necessary, part of the epitaxial layer were polished and etched away while the assembly was mounted on a temporary support, and the remaining plate 2a was then mounted on a support 4, e.g. of Au-coated Cu or of an insulating material. During thinning the thickness of the plate may be monitored by measuring the transmission of sodium light. The plate 2a may be thinner than the original depth of the region 3. In another embodiment the final plate constitutes part of an original wafer more than 50 Á thick in which a junction has been formed by diffusion, no epitaxy being used in this case. Junctions may be formed in plates which have already been thinned to less than 20 Á. The invention may be used in the manufacture of diodes, transistors, Si or GaAs field effect transistors or varactors, light emitting GaAs or GaAsP diodes which emit light from both faces or which have reflectors on one face to reinforce light emitted through the other face, or lightsensitive devices such as solar cells open to light on both faces. Thin plates carrying devices may be mounted on top of one another to give a high packing density. Conductors may be provided on both faces of a thin plate containing a device.
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