Variable-area resonant tunneling diodes using implanted in-plane gates

Variable-area resonant tunneling diodes have been fabricated using a process in which the lateral confinement is produced by an in-plane implanted gate. The basic operation of such devices is discussed, and the lateral confinement shown by both measurements and numerical modeling to be very nearly symmetrical about the resonant tunneling diode (RID) barriers. Fine structure has been observed near threshold for relatively large area devices and this has been attributed to single-electron or few-electron tunneling through donor states in the quantum well. Additional fine structure seen in the valley current of small-area devices has been shown to be consistent with the effects of lateral quantization in the system. Finally, results are presented for strip devices in which the resonant turmeling peak breaks up into numerous subpeaks on application of the gate voltage, and this is attributed to pinning of the confining potential by donors close to the RTD barriers.