The lithium flexode, a p− n junction device whose I–V characteristic is reversibly adjustable and which heretofore has been made only with germanium, has now been made with silicon. The silicon flexode was batch fabricated by doping a silicon wafer with lithium to about 8 × 10 17 atoms/cm 3 and then forming a shallow p− n alloy junction using aluminum. Experimentally, the silicon flexode was evaluated primarily as a bistable switch operating between a rectifying or diode-state ( D) and a conducting-state ( C)). Electrical signals only (with their attendant Joulean heating) were used to obtain I–V adjustment. The largest change in back resistance obtained in the silicon flexode was about five orders of magnitude. Switching from the D- to C-states ordinarily took about 1 sec. However, the inverse C to D switching process required the input of substantial power (about 1 W) and usually took several minutes, although a switching time as low as 20 sec was measured. In addition, it was found that the silicon flexode can be switched in either direction to intermediate states which remain stable at room-temperature. Lithium precipitation, after cooling from the diffusion temperature, was not observed in our experiments with both quartz-crucible and floating-zone silicon. This is at variance with previously published findings. The difference is probably related to an effect, perhaps lattice strain, introduced by our diffusion technique.