USE OF NONSTOICHIOMETRY TO FORM GAAS TUNNEL-JUNCTIONS

A tunnel diode was formed from GaAs containing excess arsenic incorpor ated by molecular beam epitaxy at reduced substrate temperatures. The incorporation of excess arsenic during growth results in a more effici ent incorporation of silicon on donor sites and beryllium on acceptor sites. The better dopant incorporation, along with trap assisted tunne ling through deep levels associated with the excess arsenic, results i n a tunnel junction with record peak current density of over 1800 A/cm (2), zero-bias specific resistance of under 1X10(-4) Ohm cm, and a roo m-temperature peak-to-valley current ratio of 28. (C) 1997 American In stitute of Physics. [S0003-6951(97)04251-4].