Charge Injection Device Array Research Articles

High-speed sequential readout for infrared CID arrays with DC-coupled injection

A high-speed readout scheme for the single-gate charge injection device (CID) linear array using DC-coupled injection (DCI) is described. In contrast to the conventional readout techniques with AC-coupled injection (ACI), DCI provides better time management in reading out the signal charge. Lower device lag is achieved by the longer injection time facilitated by DCI for a given elemental readout cycle. >

Charge-injection-device 2 × 64 element infrared array performance

Three 2 × 64 element Si:Bi accumulation-mode charge-injection-device (CID) arrays were tested at low and moderate background to evaluate their usefulness for space-based astronomical observations. Testing was conducted both in the laboratory and in ground-based telescope IR observations. The devices showed an average readout noise level below 200 equivalent electrons, a peak responsivity of 4 A/W, and a noise equivalent power of 3 × 10−17 W/Hz1/2. This sensitivity compares well with that of nonintegrating discrete extrinsic silicon photoconductors. The array well capacity was significantly smaller than predicted. The measured sensitivity makes extrinsic silicon CID arrays useful for certain astronomical applications. However, their readout efficiency and frequency response represent serious limitations in low-background applications.

Single-gate charge-injection device readout modeling and analysis

An in-depth performance analysis of the single-gate charge-injection device (CID) based on a piecewise linear charge-voltage (Q-V) model is presented. Both the voltage- and the current-type readout techniques with sequential access scheme for the linear CID arrays are considered. Heuristic views on CID charge readout efficiency degradation due to depletion loading and lag caused by injection pulse loading are illustrated. Transient and steady-state characteristics of the detector are demonstrated by a step-function response. Performance parameters of the CID array as an infrared sensor are summarized and compared to evaluate the relative merits of each readout scheme.

Ideal mode operation of an InSb charge injection device

Unlike Si or HgCdTe CID (charge injection device) arrays, which normally operate at ∼1 MHz with the presence of a ≲ 10 percent fat zero (i.e., ideal mode), current InSb CID arrays fabricated on InSb substrates can operate either at a much lower clock frequency of ∼ 10 kHz (i.e., slow charge transfer mode), or when both row and column potential wells are partially filled with a large bias charge (i.e., charge sharing mode). The slow charge transfer mode is very ineffective in reading out signal charge from a large-area array and the charge sharing mode exhibits difficulties such as reduced readout efficiency, increased line capacitance, and a large photocurrent effect. By contrast, the ideal mode is free of these problems. In this paper we describe the design and fabrication of an InSb CID array, which for the first time, successfully demonstrates the ideal mode operation.

Infrared charge-injection-device array performance at low background

Low-background tests of a 1 x 32 Si:Bi charge-injection-device (CID) IR detector array were carried out to evaluate its feasibility for space-based astronomical observations. Optimum performance was obtained at a temperature of 11 K. The device showed a peak responsivity of 4.4 A/W, an average noise level of ~670 electrons, and a minimum noise equivalent power of 3 x 10(-17) W/[equation] for 1-sec integration time. This sensitivity compares well with that of discrete extrinsic silicon photoconductors. The measured sensitivity, plus the apparent absence of anomalous effects, make extrinsic silicon CID arrays very promising for astronomical applications.