The Passivated Implanted Planar Silicon (PIPS) Detector is a product of modern semiconductor technology. In most applications, this detector replaces silicon surface barrier (SSB) detectors and diffused junction (DJ) detectors, both of which are still made the same way they were made in 1960. The PIPS detector has a number of advantages over SDB and DJ types:
1. All junction edges are buried – no epoxy edge sealant is needed or used.
2. Contacts are ion-implanted to form precise, thin, abrupt junctions for good alpha resolution.
3. Entrance window is stable and rugged – it can be cleaned readily and reliably.
4. Leakage current is typically 1/8 to 1/100 of that of SSB and DJ detectors.
5. Dead layer (window) thickness is less than that of comparable SDB or DJ detectors.
6. Standard detectors are bakeable to 100 °C – higher for special models.
The PIPS Detector is fabricated by the planar process using photolithographic techniques for defining device geometries. Proprietary techniques are used to provide precise control of the oxide passivation, and ion implantation is used to form the accurately controlled junctions necessary for low reverse leakage currents and thin entrance windows. The photolithographic technique lends itself to virtually any geometry which fits onto a diameter of 140 mm.
Resistivity of the uniform ion-implanted contacts can be controlled accurately to produce position-sensitive detectors with extremely thin entrance windows (<50 nm).
Low reverse current translates into low noise contribution. Shown by the newly introduced X-PIPS™ detector, an excellent room-temperature X-Ray detector.
Unlike SSB detectors which have raw junction edges that are epoxy sealed to achieve some measure of stability, the PIPS detector junctions are all buried within the silicon wafer. There are three major advantages to this innovation: 1) The device stability is not dependent upon an epoxy sealant; 2) There is little risk of microplasma breakdown which can afflict SSB detectors and 3) Leakage current is a small fraction of that of SSB or DJ detectors.