| 摘要 |
1,270,697. Semi-conductor devices. WESTERN ELECTRIC CO. Inc. 23 April, 1969 [23 April, 1968], No. 20677/69. Heading H1K. A semi-conductor device is formed by providing a mask on a surface of a semi-conductor body, etching the unmasked portions of the body to produce depressed regions in the surface, thermally oxidizing the depressed regions to at least partially fill them with oxide 12, removing the mask and diffusing dopants into the exposed semi-conductor surface. The device illustrated is an IMPATT diode, comprising an As-doped n+ + Si substrate 11, an As-doped n-epitaxial layer 15, which is subjected to the above-described selective etching and oxidation stages, and a P-type B-doped region 14 diffused into the mesa-like remaining portion of the layer 15. The mask may be of silicon nitride or aluminium oxide, and these materials or zirconium oxide may also be used for a final passivating layer 16. Two such devices may be formed in a common wafer, the excess semiconductor material finally being removed to separate the two devices (71, 72), Fig. 7 (not shown), which remain linked by the oxide and an electrode. If the electrode 21 is transparent or meandering in form the device may comprise an avalanche photodiode. A PNPN diode is also described (Fig. 8, not shown), in which the original wafer comprises a P-type layer on an n+ substrate, and after selective etching and oxidation of the P-type layer to form a mesa, further N-type and P-type regions are formed therein by diffusion. Avalanche transistors may also be made in accordance with the invention. |
