Title :
Capacitance and conductance of ZnxCd1-xS/ZnTe heterojunctions
Author :
Zekry, Abdelhalim ; Abdel-Naby, M. ; Ragaie, H.F. ; El Akkad, F.
Author_Institution :
Dept. of Electr. Eng., King Saud Univ., Riyadh, Saudi Arabia
fDate :
2/1/1993 12:00:00 AM
Abstract :
Capacitance-voltage and conductance-voltage characteristics of RF-sputtered ZnCdS films on ZnTe single crystals are studied as a function of frequency up to 1 MHz. It is found that the measured capacitance decreases with frequency while the conductance increases. A physical circuit model of the junction is proposed to explain this dependence. A relationship relating the junction capacitance to the polycrystalline film properties and the built-in voltage of the junction is derived. It shows that the junction capacitance is related to the average carrier concentration rather than the doping concentration of the polycrystalline material. From a C-2 versus V plot an average carrier concentration in the films which is in good agreement with that obtained by Hall measurement is obtained. The lower average electron concentration in the ZnCdS film near the substrate is due to either interdiffusion of Cd from the film into substrate or due to higher density of grain boundary states in the starting deposition portion of the film
Keywords :
II-VI semiconductors; cadmium compounds; capacitance; carrier density; electronic conduction in crystalline semiconductor thin films; p-n heterojunctions; zinc compounds; 10 kHz to 1 MHz; C-V characteristics; RF sputtered films; ZnxCd1-xS-ZnTe heterojunction; ZnTe single crystals; average carrier concentration; built-in voltage; capacitance; conductance-voltage characteristics; grain boundary states; interdiffusion; physical circuit model; polycrystalline film properties; Capacitance measurement; Capacitance-voltage characteristics; Circuits; Conductive films; Crystals; Frequency measurement; Semiconductor process modeling; Substrates; Voltage; Zinc compounds;
Journal_Title :
Electron Devices, IEEE Transactions on
