A GaAs delta‐doped tunneling diode having a &dgr;n+‐i‐&dgr;p+‐i‐&dgr;n+structure is investigated. A negative differential resistance behavior with peak‐to‐valley ratio as high as 3.1 and a peak current density of 3 kA/cm2is exhibited when the device is operated at room temperature. It becomes resistor‐like at the temperature of 77 K. Theoretical analysis, based on envelope wave function approximation, indicates that the resonant interband tunneling process is responsible for room‐temperature characteristics, while the band‐gap widening effect is responsible for low‐temperature behavior. Furthermore, the dependence of device performance on such structure parameters as doping level, and the physical dimension of the delta‐doped region, etc., is discussed, and found to agree well with experimental results.