Moo-Sup Lim

A novel in situ vacuum encapsulated lateral field emitter triode

We have designed and fabricated a novel lateral field emitter triode, which is in situ vacuum encapsulated so that any troublesome additional vacuum sealing process is not required. The device exhibits low turn-on voltage of 7 V, stable current density of 2 /spl mu/A per tip, and high transconductance of 1.7 /spl mu/S per 100 tips field emitter array at V/sub AC/=22 V. An in situ vacuum encapsulation employing recessed cavities by isotropic RIE (reactive ion etch) method and an electron beam evaporated molybdenum vacuum seal are implemented to fabricate the new field emitter triode. The superb field emitter characteristics are probably due to sub-micron dimension device structure and the pencil type lateral cathode tip employing upper and lower LOCOS oxidation.We have designed and fabricated a novel lateral field emitter triode, which is in situ vacuum encapsulated so that any troublesome additional vacuum sealing process is not required. The device exhibits low turn-on voltage of 7 V, stable current density of 2 /spl mu/A per tip, and high transconductance of 1.7 /spl mu/S per 100 tips field emitter array at V/sub AC/=22 V. An in situ vacuum encapsulation employing recessed cavities by isotropic RIE (reactive ion etch) method and an electron beam evaporated molybdenum vacuum seal are implemented to fabricate the new field emitter triode. The superb field emitter characteristics are probably due to sub-micron dimension device structure and the pencil type lateral cathode tip employing upper and lower LOCOS oxidation.

Investigation of field emission characteristics for Si-base materials: Titanium silicide, poly-Si, and single crystal Si

In vacuum microelectronics, the stability of emission current and low turn-on voltage are key factors for practical applications. In order to obtain stable and large field emission current, various materials such as molybdenum, silicon, and diamond-like-carbon have been studied for field emitter tips. Among various materials, Si-base materials have attracted a considerable interest due to its compatibility with silicon processing. In this work, we fabricated poly-Si, Si, and Ti-silicide field emitter arrays employing in-situ vacuum encapsulated lateral field emitter structures. We compared the field emission characteristics of these devices to each other focusing on turn-on voltage, emission current density, and stability of emission current.

A novel lateral field emitter triode with insitu vacuum encapsulation

We have designed and fabricated a novel lateral field emitter triode, which is in-situ vacuum encapsulated so that any troublesome additional vacuum sealing process is not required. The device exhibits low turn-on voltage of 7 V, stable current density of 2 /spl mu/A/tip at V/sub AC/=30 V, and high transconductance of 1.7 /spl mu/S at V/sub AC/=22 V. An in-situ vacuum encapsulation employing recessed cavities by isotropic RIE (Reactive Ion Etch) method and an electron beam evaporated molybdenum vacuum seals is implemented to fabricate a new field emitter triode.

In-situ vacuum-sealed lateral FEAs with low turn-on voltage and high transconductance

We have fabricated a new lateral field emitter array, in-situ vacuum-sealed, which exhibits a low turn on voltage and a high transconductance value without any additional vacuum sealing process. The vacuum-sealed lateral FEA (VLFEA) is encapsulated during the fabrication process, so that field emission characteristics can be measured without any additional vacuum environments. Experimental current-voltage (I-V) characteristics show that the anode current is field emission current obeying the linearity of the Fowler-Nordheim (F-N) plot. The experimental turn-on voltage of about 9 V is in good agreement with the extracted one from the F-N plot. In order to verify the integrity of the vacuum sealed micro-cavity, we have measured the anode current of the VLFEA both in a high vacuum chamber and in an atmospheric environment and found that the structure is well sealed. The anode currents as a function of gate voltage of the Mo-sealed VLFEA are analyzed and transconductance is extracted. The experimental results show that the VLFEA has superior field emission characteristics, such as low turn-on voltage and high transconductance, and does not require any additional troublesome vacuum sealing.

A new base resistance controlled thyristor employing trench gate and self-align corrugated p-base

A new trench-gate CB-BRT, which employs the trench gate structure in order to increase the maximum controllable current (MCC) by reducing the channel resistance, is proposed and fabricated. The experimental results show that the MCC of the trench gate CB-BRT increased by 30% and the forward voltage drop decreased by 0.2 V.

Gate Current Suppressed Lateral FEAs with Integrated TFTs

Lateral FEAs which have three terminals, stable anode current, and suppressed gate current are proposed and fabricated. In order to eliminate the path of electrons between tips and anode, the proposed FEAs are sealed by evaporation of oxide while Molybdenium in our privious work. Experimental results such as controllibility of gate electrode, a portion of the gate current for the anode current, and stability of the anode current are given. The proposed FEAs exhibit an excellent controllibility by gate electrode and stability of the emission current. The gate current of new FEAs is negligible compared with the ande current while that of the privious FEAs is about 20% of the anode current.

Investigation of field emission characteristics for Si-base materials: titanium silicide, poly-Si, and single crystal Si

In vacuum microelectronics, the stability of emission current and low turn-on voltage are key factors for practical applications. In order to obtain stable and large field emission current, various materials such as molybdenum, silicon, and diamond-like-carbon have been studied for field emitter tips. Among various materials, Si-base materials have attracted a considerable interest due to its compatibility with silicon processing. In this work, we fabricated poly-Si, Si, and Ti-silicide field emitter arrays employing in-situ vacuum encapsulated lateral field emitter structures. We compared the field emission characteristics of these devices to each other focusing on turn-on voltage, emission current density, and stability of emission current.

Undoped poly-Si tip lateral field emitter arrays with stable anode current by self-current limiting

In the field emitter arrays (FEAs), the stability of field emission current is an important issue to practical applications. There are many researches to improve the stability and uniformity of field emission current using the active devices such as Field-Effect-Transistors (FETs) and Thin Film Transistor (TFT). However, most of these devices have four terminals. In addition, the fabrication process becomes complicated due to the additional process of the integration of FETs and FEAs. In this paper, we propose a three-terminal new lateral poly-Si field emitter inherently integrated with Metal-Oxide-Semiconductor (MOS) system so that anode current is stable. Moreover, the fabrication process of the device is very simple.

A Comparison of Poly Silicon and Titanium Polycide for Field Emission Tip

We propose a novel lateral field emission triode, which does not require any additional vacuum sealing process and exhibits superb field emitter triode performance. The purpose of this paper is to compare titanium polycide tip with polycrystalline silicon tip. A new experimental results of the device, such as variation of tip material, device stability experiment, measurement of the novel device in vacuum chamber in order to verify the proposed vacuum sealing process, and transconductance characteristics at each current level. The minimum turn-on anode to cathode voltage of titanium polycide tip is considerably decreased compared with polysilicon tip. The anode current measured in 10-8 Torr vacuum chamber is similar to the anode current measured in atmospheric pressure, which shows that the proposed vacuum sealing process is reliable. The stable current of 300 µA is maintained during 60 h.

A Insitu Vacuum Encapsulated Novel Lateral Field Emitter Triode for Microwave Application

We 1 ~ o p o s e U novel lateral ,field emission triode, which does no1 require uny uddilional vacz~zi~n sealing process and exhihits superh ,field eniitler triode perjbrmunce. The p u i p x e qf this paper is to reporf U new experiiiientul dutu [?/‘the device, such US vuriulion qf tip material, device stability experiiizent, meastireinen1 of the novel device in vacuum chamber in order. to verijji the proposed vacuum ,wiling I J ~ . O C ~ S S , and transconductance charac~eristics at each current levcl. The iiiiiiiimiii turn-on cinode to cathode voltage of‘ titanium polycide tip is considcrahly dccreir.scti coii~purcd with polysilicon tip. The anode currenl nzeusured in 1 U‘’ Torr vucuunz chumhcr is similar to the anode current nzeusured in u t m o q h r i c pressure. The stable current of’300 ,uA i s maintained during 60 hours.