N‐type (P, Sb) and p‐type (B) doping of hydrogenated amorphous Si by reactive rf co‐sputtering

Abstract

PACS 73.61. Jc, 78.30.Ly, 78.66.Jg, 81.05.Gc B, P or Sb were doped into amorphous silicon films by the reactive radio-frequency co-sputtering method. The targets used were composed of silicon wafers and small about 1 mm thick chips of the respective impurity element, which were attached to the silicon wafers with silver powder cement and epoxy resins. Argon and hydrogen partial pressures used were 5 × 10 −3 and 5 × 10 −4 torr, respectively. The impurity concentration in the film was determined by secondary ion mass spectroscopy for B and P and by He backscattering spectroscopy for Sb. The substrates were kept at 200 -250 °C during deposition. Raman spectra revealed that films prepared even at 250 °C were amorphous. Heterostructures, where P-, Sb-or B-doped films were deposited on p-or n-type Si, exhibited good rectification characteristics of p -n diodes. It has been shown that the co-sputtering method can produce low-resistivity p-type (B) and n-type (P) a-Si : H films for relatively low concentrations of B and P, respectively.

Crossover from Nearest-Neighbor Hopping Conduction to Efros–Shklovskii Variable-Range Hopping Conduction in Hydrogenated Amorphous Silicon Films

“…3,4) To understand the localization of electronic states, temperature dependence of conductivity data of amorphous silicon and related alloys have been analyzed with the help of various hopping models. [5][6][7][8][9] In the amorphous silicon, the electron conduction paths are composed of s-p hybrid orbitals and carrier transport is controlled by the nearest-neighbor hopping (NNH) or the variable-range hopping (VRH) conduction. 10) In this material, it was typically found that the activation energy of the electrical conductivity decreases progressively as the temperature falls.…”

Dependence of conduction mechanisms in heavily Al-doped 4H-SiC epilayers on Al concentration

“…19) The well-known conduction mechanisms in semiconductors include band conduction, nearest-neighbor-hopping (NNH) conduction, 9,10,[20][21][22][23][24][25][26][27] and variable-range-hopping (VRH) conduction. [21][22][23][27][28][29][30][31][32] In the case that the currents due to band, NNH, and VRH conductions flow completely in parallel in the valence band, the Al acceptor level (E Al ), and the Fermi level [E F (T )], respectively, ρ(T ) can be expressed as…”

Comparison of temperature-dependent resistivity of heavily Al- and N-codoped 4H-SiC grown by physical vapor transport and heavily Al-doped 4H-SiC grown by chemical vapor deposition

“…The well-known conduction mechanisms in semiconductors include band conduction, NNH conduction, 9,10,[25][26][27][28][29][30][31][32] and VRH conduction. [26][27][28][32][33][34][35][36][37] If the currents due to band, NNH, and VRH conduction flow in parallel in the VB, at an Al acceptor level (E Al ), and around E F , respectively, the overall temperature-dependent resistivity [i.e. ρ(T)] can be expressed as…”

“…1. At (C Al − C N ) values of around 2 × 10 19 cm −3 in Fig.1, the ρ(300) values for the PVT-grown codoped samples are still slightly higher than those for the CVD-grown samples.Figure2shows Arrhenius plots of ρ(T) for the CVD-grown samples with C Al values of 2.4 × 10 19 and 3.4 × 10 19 cm −3 (▿ and ◯, respectively), and for the PVT-grown codoped sample with C Al of 3.0 × 10 19 cm −3 and C N of 2.9 × 10 18 cm −3 (•).The well-known conduction mechanisms in semiconductors include band conduction, NNH conduction,9,10,[25][26][27][28][29][30][31][32] and VRH conduction [26][27][28][32][33][34][35][36][37]. If the currents due to band, NNH, and VRH conduction flow in parallel in the VB, at an Al acceptor level (E Al ), and around E F , respectively, the overall temperature-dependent resistivity [i.e.…”