GB1286094A - Semiconductor transducer - Google Patents

Abstract

1286094 Semi-conductor devices MATSUSHITA ELECTRIC INDUSTRIAL CO Ltd 22 Aug 1969 [23 Aug 1968] 42004/69 Heading HIK A pressure sensitive semi-conductor device comprises a body having a PN junction between regions containing shallow impurities, a region containing deep impurities spaced from the junction and electrodes connected to each of the regions. As shown, Fig. 2, the device comprises an N- type region 1, a P-type region 2 and a region 3 containing a deep level impurity. Electrodes 4, 5 and 6 contact regions 1, 2 and 3 respectively and the device is operated with both electrodes 4 and 6 biased positively with respect to electrode 5. When the device is mechanically stressed current flows between electrodes 6 and 5, reverse biased junction 51 providing current amplification. The stress may be applied via electrode 6. In a modification, Fig. 4 (not shown), a plurality of mesas each containing a deep level doped region are provided above a common PN junction. The P-type region may be produced on an N- type Si substrate by epitaxial growth or diffusion and the deep level impurity may be Au added by ion implantation. The electrode 6 may form an ohmic or a rectifying contact with region 3. The stress may be applied anisotropically, uniaxially or by hydrostatic pressure. In a modification, Fig. 5 (not shown), a planar structure comprises three regions of alternate conductivity types with a region containing a deep level impurity formed in the inner region. Electrodes are provided on all four regions and the device is operated with both PN junctions reverse biased. The carriers injected by the deep level doped region under stress are amplified by the two PN junctions. The semi-conductor material may also be Ge, GaAs, GaP, InSb, InAs, or SiC and the deep level impurity may also be Cu, Ni, Co, Fe, Mn, Zn or Hg depending on the semi-conductor material and may be diffused, ion implanted, or electron beam injected into the body.