Simple, high current, antimony ion source.
A simple metal ion source capable of producing a continuous, uncontaminated, high current beam of Sb ions is presented. It produced a total ion current of 200 muA at 1 kV extraction voltage. A discharge occurred in the source at a pressure of 6x10(-4) Torr. The ion current extracted from the source increased with the 3/2 power of the extraction voltage. The perveance of the source and ion density in the plasma were 8x10(-9) and 1.8x10(11) cm(-3), respectively.
Silicon molecular beam epitaxy with antimony ion doping
A new method of ionized antimony doping of silicon molecular beam epitaxial films has been investigated. Si films were grown on Si (111) substrates by evaporation of Si from an e‐gun evaporator in ultrahigh vacuum. Sb ions were generated with an electron impact ion source. Carrier concentration of doped layers, grown at a substrate temperature of 860 °C, can be accurately controlled over the range 1016–1020 cm−3. Doping efficiency of Sb ions is 100%. Doping with ions in the range 130–1000 eV kinetic energy does not degrade the crystallographic or electrical quality of the films. For example, abrupt changes in the doping level of a composite film with three doped layers are given. The in‐depth Sb dopant profile of this film corresponds closely to the Sb ion doping schedule, which indicates that the surface segregation of Sb does not occur attendant ion doping.
GaAs–Alx Ga1−x As double‐heterostructure lasers prepared by molecular‐beam epitaxy
GaAs–Alx Ga1−x As double‐heterostructure (DH) lasers that exhibit laser properties similar to DH lasers prepared by liquid‐phase epitaxy have been prepared by molecular‐beam epitaxy. For a structure with a 0.53‐μ‐thick active layer, the as‐grown threshold current density at room temperature was 3.5×104 A/cm2, but by annealing the threshold was reduced to 4.0×103 A/cm2.