(Invited) Thin Film Transistors as Driving Devices for Attached Devices

Abstract

TFTs can be used as driving or detecting devices for purposes of optical, chemical, or biological sensing, imaging, displays, etc. Assuming the stability is not an issue, the poly-Si, IGZO, and a-Si:H TFTs were compared with respect to the device driving capability. For the drain-attached device, the maximum available power is determined by the device’s resistance and the TFT’s on-current. For the gate-attached device, the study is based on connecting a resistor and a capacitor in parallel. The raise or decay of the drain current is dependent on the RC time delay. Although the high mobility TFT has many advnatages, the low mobility TFT is adequate for certain applications. In real applications, the manufactuability and cost are important factors in choosing the TFT.

(Invited) Oxide TFT Applications: Principles and Challenges

“…For example, a sensor can be attached to a TFT to monitor the chemical concentration in the exposed gas or liquid. The former can be taken as a resistor with a resistance r and the latter can also be taken as a resistor with a resistance R that changes with the transistor operation condition, as shown in Figure 3(a) (7). When a fixed V'D is applied, the drain voltage (VD) of the TFT changes with r, as shown in Fig.…”

“…When a fixed V'D is applied, the drain voltage (VD) of the TFT changes with r, as shown in Fig. 3(b) (7). Then, R varies with VD.…”

“…Also, there is a limit on the power of the device that the TFT can drive, as shown in Fig. 3(c) (7). Above this peak power, the device cannot be fully turned on although it can be physically attached to the TFT.…”

“…In another example, a resistor and a capacitor can be connected to a TFT, which is similar to that of a touch screen display, as shown in Figure 4(a) (7). The rise and fall rates of the drain current are shown in Fig.…”