Dependence of interface states in the Si band gap on oxide atomic density and interfacial roughness

Dopant Migration-Induced Interface Dipole Effect in n-Doped GaAs/AlGaAs Terahertz Detectors

“…The migrated donor atoms release their electrons and form a positively charged region in the barrier near the interface. The quality of the heterojunction interface may be deteriorated severely by heavily doped emitters [4], and the increased interface roughness may lead to enhancement in the interface state density at the heterointerface similar to results reported in [5]. The band discontinuity can significantly be affected [6] if a dipole layer is formed across a heterointerface.…”

“…Since the donor atoms extend over a ∼30 nm from the interface, and the negative charge region is very close to the heterointerface giving t d, therefore, ΔΦ dip ≈ (σ/ε b )t = 57.6 meV, and the effective conduction band offset becomes ΔE which affects the band offset by less than 10 meV in most of the GaAs/AlGaAs heterojunctions [10]. Since the heavy doping may increase interface roughness [4] increasing the interface state density [5] and resulting in the ionized donor density (N b t ∼ 1.38 × 10 11 cm −2 ) over a larger thickness (∼30 nm) than in normal heterointerfaces (< 10 nm near the interface), the interface dipole can reduce ΔE C significantly (∼57.6 meV) in the present device. However, in the case of an intentionally introduced doping interface dipole in band offset engineering of a heterojunction [6], t is maintained to be very small as compared to d < 100 Å resulting in ΔΦ dip (eV) ≈ (σ/ε s )d. The spectral responsivity for different fields is shown in Fig.…”

Effects of substrate and anode metal annealing on InGaZnO Schottky diodes

“…The interface state density is expected to depend greatly on the interfacial roughness. 31,32 Larger film roughness causes larger interfacial area, resulting in a possibility of more interface states even if their density per real interface area remains the same. 33 Furthermore, the increased roughness was most likely caused by different thermal expansion coefficients, and the residual strain in the film may also lead to increased band-gap states.…”

Hard x-ray photoelectron spectroscopy equipment developed at beamline BL46XU of SPring-8 for industrial researches

“…Recently, Yamashita et al, have developed a method for the evaluation of the energy distribution of interface states in the semiconductor device, on the basis of the x-ray photoelectron spectroscopy under biases applied between a metal overlayer and a semiconductor layer. 7,8 The analysis of the energy shift of the semiconductor core level as a function of the bias voltage gives the energy distribution of the interface states. This method can be applied to the studies of MOS device with a thin oxide layer through which a high density tunneling current flows.…”