Use of nonstoichiometry to form GaAs tunnel junctions

A tunnel diode was formed from GaAs containing excess arsenic incorporated by molecular beam epitaxy at reduced substrate temperatures. The incorporation of excess arsenic during growth results in a more efficient incorporation of silicon on donor sites and beryllium on acceptor sites. The better dopant incorporation, along with trap assisted tunneling through deep levels associated with the excess arsenic, results in a tunnel junction with record peak current density of over $\text{1800\hspace{0.17em}}{\mathrm{A/cm}}^{\mathrm{2}},$ zero-bias specific resistance of under ${\text{1×10}}^{\text{−4}}\mathrm{\hspace{0.17em}\Omega \hspace{0.17em}}\mathrm{cm},$ and a room-temperature peak-to-valley current ratio of 28.