diffusion treatments for the manufacture of halbleiterbauelementes with a halbleiterkoerper from gallium arsenide

摘要

1,101,909. Making GaAs devices. STANDARD TELEPHONES & CABLES Ltd. 13 Jan., 1967, No. 1852/67. Heading HlK. A gallium arsenide semi-conductor device is made by depositing on the surface of a gallium arsenide body, a silicon layer doped with an acceptor impurity or a donor impurity other than silicon, and heating in an arsenic-free atmosphere to diffuse the impurity into the surface. The layer of silicon acts as a barrier to prevent oxygen diffusion. An epitaxial layer 31 of N-type GaAs is grown on a substrate 32 of NSP+/SP -type GaAs and covered with a silica layer (33, Figs. 3b and 3c, not shown) provided with a window therein. A layer (34) of Zn or Mg doped Si is deposited by sputtering over the oxide film and the window and then heated to give a diffused P-type base region (35). The silica and silicon layers are replaced by another silica layer 36 having a window therein for an emitter region. A pure layer of silicon (37, Figs. 3d and 3e, not shown) is deposited over the silica and the structure heated in an arsenic atmosphere to give a diffused N-type emitter region 38. The silicon in contact with the gallium arsenide recrystallizes and an NSP+/SP-type contact is formed on the emitter region. Alternatively the silicon layer (37) may be doped with As, Sb or P. The silicon layer is partially removed to leave an emitter contact 39. Ohmic contacts 40, 41 and 42 are provided for the device. The silicon layer containing Zn and Mg may be replaced by one containing Be, Cd or Mn, whilst the donor impurity may be Sn. Using similar techniques, a mesa or planar diode may be formed (Figs. la to Id and 2a to 2d, respectively, not shown) which may be suitable for varactor or avalanche oscillators. A plurality of devices may be formed in one slice and subsequently divided. The doped Si layer may be deposited by R.F. electric discharge in a low pressure atmosphere of SiH 4 and Zn or Mg vapour.