Porous Silicon NDR-Based High Power RF Oscillator Diode

A high power oscillation occurring on a porous silicon diode with an obvious dc N-shaped negative differential resistance (NDR) at room temperature is presented for the first time. The voltage oscillation swing was up to 12.4 V and oscillation frequency was 101.3 kHz, which belongs to the radio frequency range. The oscillation was based on a porous silicon superlattice diode structure, which was observed to provide a stable NDR with a high peak-to-valley current ratio as high as 7.9 for dc current-voltage characteristics at room temperature. A superlattice diode structure was formed by an electrochemical etching method on an n-type (100) silicon wafer with an alternating etching current. In addition, a dc constant current source was used as the power supply for the diode oscillation. In particular, two steady operating points were observed for the dc NDR current-voltage characteristics of the circuit load line. The system produced a steady oscillation between these two operating points in a harmonic form.