A semiconductor light emitting device of double hetero junction includes an active layer and clad layers. The clad layers include an n-type layer and p-type layer. The clad layers sandwich the active layer. A band gap energy of the clad layers is larger than that of the active layer. The band gap energy of the n-type clad layer is smaller than of the p-type clad layer.

Semiconductor light emitting device and manufacturing method therefor

We have studied the effects of adding small amounts of In (0.2–1.2%) to GaAs grown by molecular beam epitaxy. The density of four electron traps decreases in concentration by an order of magnitude, and the peak intensities of prominent emissions in the excitonic spectra are reduced with increase in In content. Based on the higher surface migration rate of In, compared to Ga, at the growth temperatures it is apparent that the traps and the excitonic transitions are related to point defects. This agrees with earlier observations by F. Briones and D. M. Collins [J. Electron. Mater. 11, 847 (1982)] and B. J. Skromme, S. S. Bose, B. Lee, T. S. Low, T. R. Lepkowski, R‐Y. DeJule, G. E. Stillman, and J. C. M. Hwang [J. Appl. Phys. 58, 4702 (1985)].

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Low defect densities in molecular beam epitaxial GaAs achieved by isoelectronic In doping

The effects of isoelectronic doping of GaAs by In or Sb on the electron deep levels in n‐GaAs grown by molecular‐beam epitaxy have been investigated in the growth temperature range 500–600 °C for Si doping levels of 4–7×1016 cm−3 and As‐stabilized conditions. The two dominant traps M3 and M6 are drastically reduced in concentration by up to three orders of magnitude for M3 (from 1015 cm−3 down to <1012 cm−3) and two and a half orders of magnitude for M6 by introducing 0.2–1 at.% In or Sb and increasing growth temperatures from 500 to 550 °C. The trap concentrations of M3 and M6 were also significantly reduced by increasing the growth temperature to 600 °C without In or Sb doping and by decreasing the growth rate from 1.0 to 0.3 μm/h. The incorporation coefficients of In and Sb have been measured and are found to decrease with increasing growth temperature. The growths with high M3 and M6 trap densities are shown to have short minority‐carrier diffusion lengths. Indium isoelectronic doping, which is presum...

Trap suppression by isoelectronic In or Sb doping in Si‐doped n‐GaAs grown by molecular‐beam epitaxy

A buried five‐period 94 A Al0.3Ga0.7As/ 56 A GaAs superlattice is employed to improve the dynamic retention of electrons at an AlGaAs/GaAs heterojunction. The improvement is attributed to the impurity trapping and gettering properties of this superlattice and the amount of time our molecular beam epitaxy system had been closed. Electron retention time constants of 29 s were obtained at a temperature of 77 K. This is more than 200 times longer than previously reported time constants and more than adequate for dynamic logic or memory applications compatible with AlGaAs/GaAs heterojunction field‐effect transistors.

Effect of a buried superlattice on the dynamic storage of electrons at the AlGaAs/GaAs heterojunction

We have studied the effects of adding small amounts of indium (06 at %) in GaAs layers grown by molecular beam epitaxy on GaAs substrates Photoluminescence spectra showed that epilayers of high crystal quality were obtained, and electron beam induced current microscopy revealed a number of misfit dislocations near the interface and a dislocation‐free zone near the top surface We observed several well known deep traps in the dislocation‐free zone, albeit at much lower concentrations in comparison to indium‐free, otherwise identical epilayers We failed to observe any traps in the misfit dislocation zone If, as is widely held, we assume that these traps are due to point defects and their complexes, a possible explanation of the absence of traps in the dislocation zone is that the traps provide the point defects necessary for the creation and climb of the misfit dislocations

Deep states and misfit dislocations in indium‐doped GaAs layers grown by molecular beam epitaxy

By applying a single LPE-grown isoelectronically doped strained layer, on top of a conventional InP wafer, a strong reduction of dislocation and deep level density occurs. As a result an improvement in minority carrier lifetime and diffusion length and a better uniformity across the wafer is achieved. This is demonstrated by the comparison of p-n diodes fabricated with and without the strained layer.

N. Emeis

Papers

Minority carrier lifetime improvement by single strained layer epitaxy of InP