The space charge limited current and huge linear magnetoresistance in silicon

Abstract

Huge magnetoresistance in space charge regime attracts broad interest on non-equilibrium carrier transport under high electric field. However, the accurate fitting for the current-voltage curves from Ohmic to space charge regime under magnetic fields has not been achieved quantitatively. We conjecture that the localized intensive charge dynamic should be taken into consideration. Here, by introducing a field-dependent dielectric constant, for the first time, we successfully simulate the current-voltage curves of covalent crystal silicon wafers under different magnetic fields (0–1 Tesla). The simulation reveals that the optical phonon, instead of the acoustic phonon, plays a major role for the carriers transport under magnetic fields in space charge regime.

Space Charge Effect and Resistance Switching in Doped Monocrystalline Silicones

“…The discrepancy may be attributed to the distribution of dopants along the surface and the energy level of dopants in the band gap. Our previous work showed that a large magnetoresistance and the successive Ohmic and MG regimes could be observed in a current perpendicular to plane (CPP) configuration [6], which can be well simulated by a model proposed by Zhang and Pantelides [2]. In fact, it has been predicted in theory that an ETF regime could be "stretched" to different voltage ranges by the concentration of dopants [1].…”

“…When all available states in the band gap are filled with carriers, the I-V curve rises up and conforms to the square law (I∝V 2 ). Hence, another critical voltage V U for the ETF regime is defined [1][2][3][4][5][6], and the MG regime can be identified. Two critical voltages, V L and V U , are the lower and upper limitations of the ETF regime.…”

“…1 More detailed work may be able to probe a single, deep, trap level with various concentrations of dopants from multiple ETF regimes as suggested by Zhang and Pantelides [2]. SCE leads to a non-uniform distribution of internal voltages between electrodes [1][2][3][4][5][6][7][8]. Figure 2a shows I-V curves of device 0129-7# with a different L value.…”

“…Next, the concentrations The samples were heavily doped n-Si with resistivity 10-20 Ω·cm and carrier densitỹ 2.1 × 10 14 cm −3 at room temperature. We considered that the observed SCE manifested the role of dopants on the motions of injected carriers under an external electric field [1][2][3][4][5][6]. The ionized dopants, which were in fact the effective traps for carriers in a band gap, exert a push-back effect on the motions of carriers.…”

“…It is assumed that dopants provide carriers and weaken SCE, while ionized dopants capture carriers and strengthen SCE. Thus, the shape of a current-voltage (I-V) curve is modulated by the fast dynamics of ionization or filling process [1][2][3][4][5][6]. The dynamics of carriers may have a characteristic of historical memory due to the localized charge accumulation or dissipation.…”