S. Miyano

A novel vertical current limiter fabricated with a deep trench forming technology for highly reliable field emitter arrays

We have developed highly reliable field emitter arrays with a novel vertical current limiter fabricated with a deep trench forming technology. The vertical current limiter has a local current-control function that automatically prevents fatal arc failure, and it has low resistance when used in the normal operation of a field emitter array. It has demonstrated a breakdown voltage as high as 120 V and a negligible increase in operation voltage, i.e., Vg of 70 V at 1 /spl mu/A/tip with an emitter cone density of more than 5/spl times/10/sup 7/ emitters/cm/sup 2/.

Electron gun design for traveling wave tubes (TWTs) using a field emitter array (FEA) cathode

We first built two traveling wave tubes (TWTs) using a Spindt-type field emitter array (FEA) cathode. The first FEA-TWT achieved excellent RF performances. However its beam transmission ratio was only 82%, in contrast with more than 99% of a conventional TWT. To improve the beam transmission ratio and other characteristics, we re-designed the FEA electron gun and fabricated a second experimental FEA-TWT. At the current less than 20 mA, the beam transmission ratio of the second TWT was improved as high as 98%. However, when the current was more than 20 mA, space charge effect became significant and beam transmission ratio was rapidly degraded. The test results indicated that the design criteria for FEA electron guns needed to take into consideration the strong influence of space charge and how a good beam transmission ratio could be obtained.

Fully large-scale integration-process-compatible Si field emitter technology with high controllability of emitter height and sharpness

We developed a fully large-scale integration (LSI)-process-compatible technology with excellent control of emitter shape for the first time. The fabricated emitter tip configuration has two-step-cone shape whose upper and lower cone configurations are controllable independently. While the upper parts determine the emitter tip sharpness and the apex angle, the lower parts determine the emitter height by utilizing two-step thermal oxidation for emitter tip sharpening in addition to anisotropic reactive ion etching for the emitter height control. The stable and uniform thermal oxidation for sharpening emitters produces excellent uniformity, and the process, without liftoff, is matched with Si LSI technology completely. The obtained 1944 tip emitter with 800 nm gate diameter showed low threshold voltage of 35 V.

An integrated poly-Si TFT current data driver with a data-line pre-charge function

We have developed an integrated poly-Si TFT current data driver with a data-line pre-charge function for active-matrix organic light-emitting diode (AMOLED) displays. The current data driver is capable of outputting highly accurate (±0.8%) current determined by 6-bit digital input data. A novel current-programming approach employing a data-line pre-charge function helps achieve accurate current programming at low brightness. A 1.9-in. 120 x 136-pixel AMOLED display using these circuits was demonstrated.

Si field emitter array with 90-nm-diameter gate holes

We have successfully developed an extremely scaled-down Si field emitter array with 90-nm-diameter gates. The developed field emitter array has a unique two-step thick insulator underneath the gate electrode, which enables the insulator to be kept thick and which enables the long creeping distance between the emitter and the gate electrodes to be maintained even if the gate diameter is reduced. A fabricated field emitter array has an extremely small gate diameter of 90 nm and shows a low threshold voltage of 22 V at 1 nA/tip.

A field-emitter-array cathode-ray tube (FEA-CRT)

High-resolution bright CRT monitors with Spindt-type field-emitter arrays (FEA-CRTs) as electron guns have been realized for the first time. The FEA chip consists of 868 electron sources arranged within an emitter circle 50 μm in diameter and a vertical current limiter (VECTL) which protects the FEA chips from damage caused by an arc electric discharge. The FEA-CRT has a minimum electron beam diameter of 0.84 mm at 18 kV and 100 μA.

Novel field emitter array technology for subhalf-micron diameter gates

We have successfully developed a novel Field Emitter Array (FEA) technology with low-leakage current between each emitter and its sub-half-micron diameter gate. This FEA has 0.38 micron gates, its emission threshold voltage is 24 V, and its leakage current has been reduced to less than a tenth of previous levels.

A novel field emitter array technology for sub-half-micron diameter gates

We have successfully developed a novel Field Emitter Array (FEA) technology with low-leakage current between each emitter and its sub-half-micron diameter gate. This FEA has 0.38 micron gates, its emission threshold voltage is 24 V, and its leakage current has been reduced to less than a tenth of previous levels.

A fully-LSI-process-compatible Si field emitter technology with high controllability of emitter height and sharpness

We developed a fully-LSI-process-compatible technology with excellent control of emitter shape for the first time. The fabricated emitter tip configuration has two-step-cone shape whose upper and lower cone configurations are controllable independently. While the upper parts determine the emitter tip sharpness and the apex angle, the lower parts determine the emitter height by utilizing two-step thermal oxidation for emitter tip sharpening in addition to anisotropic RIE for the emitter height control. The stable and uniform thermal oxidation for sharpening emitters realizes excellent uniformity, and the process without lift-off process is matched with Si LSI technology completely. The obtained 1944-tip emitter with 800 nm gate diameter showed low threshold voltage of 35 V.