Backside-illuminated silicon photodiode array for an integrated spectrometer

A p/sup +/-n, backside-illuminated photodiode array, to be used in an integrated silicon spectrometer, has been fabricated and characterized. For this type of application, illumination from the back is essential. The array is suspended in a nitride membrane for enhanced electrical and thermal isolation from the micromachined bulk. To prevent illumination from the front, the array is entirely covered with an aluminum layer, which also enhances the spectral responsivity. A model is described with which the performance of the backside-illuminated array was predicted. Furthermore, the performance of the photodiode array is compared to that of a conventional, front-illuminated array.