The examination of effects of the elastic strain energy of dislocations on electri-city / electronic properties of III-V group compounds

m SUMMARY PhD Thesis THE EX4MINA TION OF EFFECTS OF THE ELASTIC STRAIN ENERGY OF DISLOCA TIONS ON ELECTRICITY / ELECTRONIC PROPERTIES OF III-V GROUP COMPOUNDS. YüdmmAYDO?DU Fırat University Graduate School of Science and Technology Department of Physics 1994, page: 127 In this study, n-GaAs (100) plane has been used as substrate and some dislocations of 60° have been produced supplying different indentations on surface at 300 K. Firstly, n-GaAs (100) substrates were echled chemically in the solution 1; HNC^, 2 ; H20 for 15 minutes at 20 °C. From optical and electron microscopic observation the dislocation density were found as 5xl09 m"2. Afta the indentations have been applied the dislocations densities were found as 8.15xl014 nr2, 32.89xl014 nr2, 74.21xl014 nr2 for 100 gr, 200 gr and 300 gr indentations, respectivery. The elastic strain energy of 60° dislocation produced by indentations have been calculated by means of computer program and it was found to be 84 mJ/m2 for per unit dislocation. Then, the metal-semiconductor contacts were made from non-indented and indented n-Ga4s (100) surfaces. In order to determine the effects of indentations and 60° dislocations, I-V and C-V characteristics have been investigated at the temperatures 300 K and 77 K. The barrier height, q^ ; diffusion potential, Vd ; carrier density, Nd ; excess capacitance, C0 ; the series resistance of Schottky diode, R ; ideality factor, n were found as 0,68 eV, 0?8 eV, 2.25x1023 m"3. 1 10 pF,22.3 ohm,1.1 19 respectively at the sample without indentation For the metal-semiconductor contacts with the indentation, from the characteristics of I-V, C-V at 300 K, the qtyBa,Vd, Nd, C<,, R, n values were found as 0.70-0.95 eV, 0.92-1.25 eV, 2.19xl023-1.92xl023 nr3, 230-295 pF, 47-101 ohm, 1.30-2.38 and from the characteristics of C-V at 77 K the q^,Vd, Nd, C0, values were found as 0.90-1.15 eV, 1.05-1.32 eV, 1.86x1022 -1.39x1 022 m"3,240-340 pF respectively. As seen these results, the q^,Vd, C0, R and n values increase 5and Nd value decreases with the increasing indentation rate. Some important hysteresis were also found in the I-V and C-V characteristics related to indentation rate and dislocation densities. Consequently, it was reached the following important result ; the increasing indentation rate and dislocation density have enlarged the region of band gap on the Fermi Level of semiconductor. KEY WORDS :Dislocation, Schottky contact, Hl-V Compounds, GaAs, Metal-semiconductor Barrier height, Indentation