Ultrathin silicon dioxide layers with a low leakage current density formed by chemical oxidation of Si

Abstract

Chemical oxidation of Si by use of azeotrope of nitric acid and water can form 1.4-nm-thick silicon dioxide layers with a leakage current density as low as those of thermally grown SiO2 layers. The capacitance–voltage (C–V) curves for these ultrathin chemical SiO2 layers have been measured due to the low leakage current density. The leakage current density is further decreased to ∼1/5 (cf. 0.4 A/cm2 at the forward gate bias of 1 V) by post-metallization annealing at 200 °C in hydrogen. Photoelectron spectroscopy and C–V measurements show that this decrease results from (i) increase in the energy discontinuity at the Si/SiO2 interface, and (ii) elimination of Si/SiO2 interface states and SiO2 gap states.

Atomic layer deposition precursor step repetition and surface plasma pretreatment influence on semiconductor–insulator–semiconductor heterojunction solar cell

“…53 As a result in MOS structures the leakage current density J Leak was reduced. 54,55 In due consideration the hydrogen plasma pretreatment effects the same interface passivation.…”

Passivation of a-Si:H-based structures in KCN and HCN solutions and its application on p-i-n solar cell

“…Sixty-eight percent aqueous solution of HNO 3 at temperature of 121 C during 30 min was used to create silicon dioxide layer in [5]. The H 2 O 2 [6] or H 2 SO 4 /H 2 O 2 solutions [7] can be also applied for the same purposes.…”

Fabrication of Al2O3/Al structure by nitric acid oxidation at room temperature

“…A low temperature oxidation method using HNO 3 , applicable to Si [6][7][8][9][10][11] and SiC devices [12][13][14][15], has been developed by us. Immersion of Si wafers in azeotropic HNO 3 (i.e., 68wt% HNO 3 aqueous solutions at 120°C) forms an ultrathin (1.2∼1.4 nm) SiO 2 layer with a leakage current density lower than those of thermally grown SiO 2 with the same thickness [6][7][8].…”

“…Immersion of Si wafers in azeotropic HNO 3 (i.e., 68wt% HNO 3 aqueous solutions at 120°C) forms an ultrathin (1.2∼1.4 nm) SiO 2 layer with a leakage current density lower than those of thermally grown SiO 2 with the same thickness [6][7][8]. Si oxidation by use of 98wt% HNO 3 aqueous solutions can produce an ultrathin SiO 2 layer with a lower leakage current density, i.e., lower than that of a silicon oxynitride layer with the same equivalent oxide thickness [9].…”