Negative Oxide Charge in Thermally Oxidized Cr-Contaminated n-Type Silicon Wafers

Abstract

We study analytically and numerically the effect of a periodic perturbation in the index of refraction of a nonlinear optical medium. Using a one-dimensional model for monochromatic waves incident on the medium, we find that near reionancc between the perturbation and the modulation of the electric field there can be a significant enhancement of optical bistability in the low intensity regime. In particular, we discuss in detail the case of the primary resonance, which is responsible for the most significant effects, and show how one can optimize the bistability curve for the implementation of an optical switch, based on the information provided by the resonance structure.

Collapse of Cr(OH)3/n‐Si Schottky barrier and growth of atomic bridging–type surface photovoltages in Cr‐deposited n‐type Si(001) wafers

“…With air exposure time, the level height of the AC SPV in n‐type Si wafers is reduced, possibly because the Cr(OH) 3 becomes Cr 2 O 3 through the following equation: causing the height of the Schottky barrier to go down, and finally it may collapse. In Cr aqueous solution–rinsed n‐type Si(001) wafers oxidized at temperatures between 550 °C and 900 °C, the AC SPV appears, indicating that a metal‐induced negative oxide charge may be created in the form of (CrOSi) − and/or CrO 2 − networks in analogy with (AlOSi) − or (FeOSi) − demonstrated previously. However, definite evidence is not yet been obtained in reference to the process in which the transition happens.…”

“…The appearance of this negative charge convinced some of the trivalent atoms, Cr 3+ , to replace the tetravalent Si ion, Si 4+ , in the SiO 2 /Cr 2 O 3 thin film by the atomic bridging mechanism, possibly forming (CrOSi) − and/or CrO 2 − networks as well as the (AlOSi) − or (FeOSi) − network model demonstrated previously . Therefore, the Cr‐induced negative oxide charge can be described as (CrOSi) − and/or CrO 2 − networks …”

“…[9][10][11][12] Therefore, the Cr-induced negative oxide charge can be described as (CrOSi) À and/or CrO 2 À networks. [19]…”

Translation from Schottky Barrier to Atomic Bridging-Type Surface Photovoltages in Cr-Aqueous-Solution-Rinsed Si(001) Wafers

“…In Cr-aqueous-solution-rinsed n-type Si(001) wafers oxidized at temperatures between 550 and 900 C, the AC SPV appears, indicating that a metal-induced negative oxide charge may be created in the form of (CrOSi) À and/or CrO 2 À networks. 20) However, definite evidence has not been obtained yet for the process of how the transition from the Schottky barrier to the atomic bridging-type AC SPV occurs. Both types of Cr(OH) 3 /Si and SiO 2 /Si interfaces can be detected with the frequency-dependent AC SPV method.…”

Anomalous Oxide Charge Variation Identified by Alternating Current Surface Photovoltage Method in Cr-Aqueous-Solution-Rinsed p-Type Si(001) Wafers Exposed to Air

“…The existence of a metal-induced negative oxide charge 1) has been confirmed in oxidized silicon (Si) thin films contaminated with aluminum (Al), [2][3][4][5][6] iron (Fe) 7) and chromium (Cr) 8) solutions by the AC surface photovoltage (SPV) method. [9][10][11][12][13][14][15][16][17] This is postulated to be atomic-bridgingtype AC SPV.…”