Electrical, optical, and structural characterization of p‐type N‐doped SnO thin films prepared by thermal oxidation of sputtered SnN_x thin films

Abstract

We present a study of electrical and optical properties of nitrogen-doped tin oxide thin films deposited on glass by the DC Magnetron Sputtering method. The deposition conditions to obtain p-type thin films were a relative partial pressure between 7% and 11% (N 2 and/or O 2 ), a total working pressure of 1.8 mTorr and a plasma power of 30 W. The deposited thin films were oxidized after annealing at 250°C for 30 minutes. X-ray diffraction results showed that the asdeposited thin films exhibit a Sn tetragonal structure, and after annealing, they showed SnO tetragonal structure. X-ray photoelectron spectroscopy results showed the presence of nitrogen in the samples before and after annealing. The measured physical parameters of the thin films were optical band gap between 1.92 and 2.68 eV, resistivity between 0.52 and 5.46 Ωcm, a concentration of p-type carriers between 10 18 and 10 19 cm −3 , and a Hall mobility between 0.1 and 1.94 cm 2 V −1 s −1 . These thin films were used to fabricate p-type thin film transistors. the thin film crystalline phase, in contrast with larger ionic sizes which could modify this crystalline phase. The focus of this work is to synthesize and characterize p-type N-doped SnO thin films with tetragonal structure using the DC sputtering method. The resulting samples showed different electronic, electrical, and optical properties due to the nitrogen content, and they were used as transparent p-type semiconductors in the fabrication of TFTs. | EXPERIMENTAL DETAILSSnN x , SnO, and SnO x N y thin films were deposited on substrates of Corning 2948 glass (cleaned ultrasonically) by DC reactive magnetron sputtering using a tin target (purity of 99.99%). The deposition parameters used to grow the thin films were a working pressure of 1.8 mTorr, a plasma DC power of 30 W, and relative partial pressure of the reactive gas (RG pp ) between 6% and 17%. The relative partial pressure was calculated from the nitrogen (pN 2 ), oxygen (pO 2 ), and argon (pAr) partial pressures obtained from a residual gas analyzer and using the relation RG pp = (pN 2 + pO 2 )/(pAr + pN 2 + pO 2 ). The as-deposited thin films were oxidized by annealing in a tubular furnace at 250°C for 30 minutes under a continuous gas flow (90% of N 2 and 10% of O 2 ). Depending on the reactive gas, the thin films obtained after annealing were called SnO for oxygen (RG pp = O pp ), SnO:N for nitrogen (RG pp = N pp ), or SnN x O y for oxygen plus nitrogen (RG pp = N pp + O pp ). The crystalline structures of the samples were recorded by X-ray diffraction using a Rigaku Ultima III diffractometer operated at 45 kV and 40 mA with a Cu Kα = 1.5406 Å radiation source. The chemical states and presence of nitrogen in the films were determined by Xray photoelectron spectroscopy (XPS), using a VersaProbe II from PHI with a monochromatic Al Kα (1486.6 eV) radiation source. The charge effects in the XPS spectra were corrected using the value of the binding energy of carbon 1 second peak at 284.5 eV. The surface morphology of films was studied by an at...

SnOx thin films with tunable conductivity for fabrication of p–n homo‐junction

“…27,28 SnO x thin film, which enhances its p-type mobility. 3,21,29 Figure 3A also shows the effect of annealing on XRD measurements for three samples of SnO x deposited at a ppO 2 of 8.0% and annealed to 160 C, 180 C, and 200 C. These three patterns reveal a mixture of Sn and SnO crystalline phases; however, the film annealed at 160 C presented a peak at 44.9 , which suggests there is an amount of Sn traces higher than that in the other two films. In the sample annealed at 200 C, the intensity of the SnO XRD peaks was reduced, and the intensity of the (110) peak increased compared with the intensity of the (101) peak.…”

Influence of post-annealing on structural, optical and electrical properties of tin nitride thin films prepared by atomic layer deposition

“…Many methods have been pursued to prepare tin nitride thin films, including chemical vapor deposition (CVD), plasma-enhanced CVD, magnetron, or radio-frequency (RF) sputtering [15][16][17][18][19][20][21][22][23][24][25][26][27][28]. Among these, RF sputtering is the most frequently used technique to grow tin nitride thin films from tin in a nitrogen-containing atmosphere.…”

Investigation of the effect of adding a moderate amount of hydrogen on the properties of tin oxide films deposited by DC magnetron sputtering

“…With regard to the above limitations, the utilization of the new approaches to synthesizing SnO plays a key role in improving the SnO film properties. Garzon-Fontecha et al 12) showed that SnO film deposition in a nitrogen-containing atmosphere can lead to the substitution of O and Sn atoms by nitrogen ones. This substitution leads to changes in the optical and electrical properties, including a decrease in transmittance and an increase in the carrier concentration of holes.…”