Punch-through currents and floating strip potentials in silicon detectors

Spatial resolution of double-sided silicon microstrip detectors for the PAMELA apparatus

“…Bias resistors are used to connect each strip to the guard rings, which are kept at a fixed potential. On the junction side the punch-through technology [14] with an additional foxfet electrode [15] has been exploited to have R B > 50 MΩ; on the ohmic side polysilicon resistors have been used and the corresponding resistance is greater than 10 MΩ. The measured leakage current is of the order of 1 nA/strip.…”

Interstrip characteristics of n-on-p FZ silicon detectors

“…Ac-coupled sensors are susceptible to very large voltages between the metal readout traces (held to ground through the front-end electronics) and the strip implants in the case of large charge accumulation in the bulk, for instance in the case of beam losses [6]. Since the field inside of the sensor breaks down, these large voltages on the implants can reach the order of half the bias voltage, and thus can exceed the specification for the hold-off voltage of the coupling capacitor, which are typically tested to 100V.…”

“…Since the field inside of the sensor breaks down, these large voltages on the implants can reach the order of half the bias voltage, and thus can exceed the specification for the hold-off voltage of the coupling capacitor, which are typically tested to 100V. In order to prevent these large voltages, the punch-through (reach-through) effect is used [6], where implants in close proximity will effectively be shorted together if the voltage between them exceeds a geometry dependent voltage. This provides an effective over-voltage protection for single strips, which get shorted to the bias line in the case of voltages in excess of the punch-though protection ("PTP") voltage.…”

Evaluation of FOXFET biased ac-coupled silicon strip detector prototypes for CDF SVX upgrade

“…To circumvent the extra processing step required for polysilicon resistor processing and the rather difficult tuning of the process to obtain uniform and high enough resistance values throughout the large detector area, alternative methods for strip biasing have been devised. These include the usage of electron accumulation layer resistance for n+-strips [ 4] or the usage of the phenomenon known as the punch-through effect for p+ -sttips [5,6]. In this paper we present measurement results about the operation and radiation resistance of detectors with a punch-through effect based biasing structure known as a Field OXide Field-Effect Transistor (FOXFET) [7], and present a model describing the FOXFET behavior.…”