Novel Luminescence Band in Silicon Implanted with Phosphorus and Boron

  • PDF / 187,929 Bytes
  • 4 Pages / 420.48 x 639 pts Page_size
  • 91 Downloads / 226 Views

DOWNLOAD

REPORT


NOVEL LUMINESCENCE BAND IN SILICON IMPLANTED WITH PHOSPHORUS AND BORON A.K.SRIVASTAVA*, D.K.SHARMA*, AND V. PREMCHANDRANS* *Tata Institute of Fundamental Bombay-400005, India **Indian Telephone Industries, 560016, India.

K.L.NARASIMHAN*,

D.SARKAR**

Research,

Homi Bhabha

Doorvani

Nagar,

Road,

Bangalore

ABSTRACT Photoluminescence measurements on silicon implanted with boron, phosphorus, and dual implanted with phosphorus and boron are reported. A high intensity luminescence band between 0.9-1.03 eV is observed in the samples with dual implantation of boron and phosphorus. The luminescence band has similar spectral characteristics as that of the 1.018 eV W or II band which is observed in silicon samples irradiated with neutrons or ions. However the annealing behaviour of the luminescence band observed in our samples differs considerably from that of the W band, whose intensity increases on annealing at 525 K and is quenched on heating to 600 K. The luminescence band in our samples is not annealed out even at 900 C. The temperature dependence of the intensity of the luminescence band is also studied. It shows excitonic behaviour with an activation energy of 52 meV.

INTRODUCTION Defects induced by modern processing techniques in silicon are a subject of current interest. Ion-implantation is one of the most commonly used techniques in silicon technology. The technique is inherently defect prone due to the high energy ion bombardment. The simple defects generated during the bombardment can give rise to more complex defects during post implantation annealing. Some of these defects can participate in radiative recombinations giving rise to luminescence[I]. We report the results of low temperature photoluminescence measurements on thermally annealed phosphorus and boron implanted silicon. The samples subjected to dual implantation of boron and phosphorus show a very strong luminescence peak at 1.018eV and sattelite peaks at lower energies. The intensity of this peak drops rapidly above 40K with an activation energy of 52 meV.

EXPERIMENTAL

TECHNIQUES

The phosphorus and boron doped silicon substrates with resistivities 3-5 ohm-cm are implanted with P ( 180 keV, 10'5 ions cm-2) and B (80 keV, 10'5 ions cm-2 ). Some samples are dual implanted with P and B. The implantation energies for boron and phosphorus are adjusted to give very sini]uar doping profiles for both impurities. The samples are thermally annealed at 900 C for 30miri. fullowed by slow

Mat. Res. Soc. Symp. Proc. Vol. 163. c 1990 Materials Research Society

270

(virgin control sample 8 hrs. A over 450C cooling to for fashion in a similar annealed was also substrate) comparison. For the photoluminescence measurements the are to 12 K in a close cycle He refrigerator samples cooled (488nm). excited by a He-Ne laser(632nm) or an Ar ion laser analysed by a 0.67m from the samples are The luminescence N2 cooled Ge and detected by a liquid grating monochromator amplifier. photodiode connected to a lock-in

RESULTS

AND DISCUSSION

A typical luminescence spect

Data Loading...