Avalanche Noise in Al0.52In0.48P Diodes

Multiplication and avalanche excess noise measurements have been undertaken on a series of AlInP homo-junction p-i-n and n-i-p diodes with i region widths ranging from 0.04 to 0.89 mu m, using 442 and 460 nm wavelength light. Low dark currents of <170 nA cm(-2) at 95% of breakdown voltage were obtained in all the devices because of its wide bandgap and there was no tunneling dark current present even at high fields >1000 kV/cm. For a given multiplication factor, the excess noise decreased as the avalanche width decreased due to the dead-space effect. Using 460 nm wavelength light, measurements showed that a separate absorption multiplication avalanche photodiode with a nominal multiplication region width of 0.2 mu m had an effective k (hole to electron ionization coefficient ratio) of similar to 0.3.