Nontrivial capacitance behavior, including a negative capacitance (NC) effect, observed in a variety of semiconductor devices, is discussed emphasizing the physical mechanism and the theoretical interpretation of experimental data. The correct interpretation of NC can be based on the analysis of the time-domain transient current in response to a small voltage step or impulse, involving a self-consistent treatment of all relevant physical effects (carrier transport, injection, recharging, etc.). NC appears in the case of the nonmonotonic or positive-valued behavior of the time-derivative of the transient current in response to a small voltage step. The time-domain transient current approach is illustrated by simulation results and experimental studies of quantum well infrared photodetectors (QWIPs). The NC effect in QWIPs has been predicted theoretically and confirmed experimentally. The huge NC phenomenon in QWIP's is due to the nonequilibrium transient injection from the emitter caused by the properties of the injection barrier and the inertia of the QW recharging.

Negative capacitance effect in semiconductor devices

Ferroelectric Negative Capacitance Field Effect Transistor

Bias, frequency and temperature-dependent capacitance characteristics of p-GaAs homojunction interfacial work-function internal photoemission (HIWIP) far-infrared detectors are reported. A strong negative capacitance phenomenon has been observed. Unlike in other devices, even up to 1 MHz in HIWIP, the negative capacitance value keeps increasing with frequency, giving a stronger effect. The origin of this effect is believed to be due to the carrier capture and emission at interface states. Fitting data based on charging-discharging current and the inertial conducting current model show good agreement with the experimental observations.

http://physics.gsu.edu/perera/pdf/APL743167.pdf

Negative capacitance of GaAs homojunction far-infrared detectors

The frequency dependence of capacitance-voltage (C-V) and conductance-voltage (G/ω-V) characteristics of the Au/polyvinyl alcohol (Ni, Zn-doped)/n-Si Schottky barrier diodes (SBDs) was investigated in the frequency range of 3 kHz-3 MHz at room temperature by considering series resistance (Rs) and interface states (Nss) effects. The C-V and G/ω-V characteristics confirm that the Rs and Nss are important parameters that strongly influence the electrical parameters of SBDs. The C-V plots show an intersection point (∼2.9 V) at low frequencies (f ≤ 30 kHz) and then take negative values, which is known as negative capacitance (NC) behavior. The negativity of the C increases with the decreasing frequency in the forward bias voltage region, and this decrement in the NC corresponds to the increment in the conductance. Also, the forward bias C-V plots show an anomalous peak in the voltage range of 1.55–1.9 V depending on the frequency such that the anomalous peaks shift toward positive voltage values with the incre...

The origin of anomalous peak and negative capacitance in the forward bias capacitance-voltage characteristics of Au/PVA/n-Si structures

The negative capacitance behavior in light-emitting diodes and laser diodes has been observed and characterized by using ac admittance–voltage method. Experimental results proved that the strong negative capacitance behavior is always accompanied by remarkable light emission. We confirmed that the negative capacitance is an effect of the junction instead of other behavior or measurement error. We presented a numerical calculation by solving one dimension continuity equation based on a simple diode model. The results show that the negative capacitance behavior in light-emitting diodes has great relation to injected carriers recombination in the active region of luminescence.

Masanao Kitagawa

Papers

Negative Capacitance of Silicon Diode with Deep Level Traps