Tomasz Grzebyk

Micropump for Generation and Control of Vacuum Inside Miniature Devices

The microengineered MEMS-type ion-sorption micropump with field-emission electron source has been shown. Effective emission properties of the carbon nanotubes cathode ensure satisfactory efficiency of residual gas ionization, showing possibility of active pumping of circa 0.05 cm3 volume down to 10-5 hPa. Measurement of ion current allows estimation of vacuum level inside the microcavity.

Lateral MEMS-Type Field Emission Electron Source

This paper describes a microelectromechanical-system-type field emission electron source fabricated as a planar silicon structure bonded with a glass substrate. It consists of a carbon nanotube cathode, beam formation electrodes, and silicon glass vacuum housing, all made in a uniform technological process. The current-voltage characteristics obtained inside a reference vacuum chamber for the two-, three-, and four-electrode configurations have been presented. The possibility of generation of a focused electron beam as well as gas ionization has been investigated. In addition, the lateral electron source has been integrated on the chip with a miniature ion-sorption vacuum pump and hermetically sealed. The use of the micropump significantly improved the stability of field emission current.

MEMS-Type Self-Packaged Field-Emission Electron Source

This paper describes a Micro-Electro-Mechanical System-type self-packaged field-emission electron source with a carbon nanotube cathode. It is a multilayer silicon-glass structure, fabricated by the use of the multiple anodic bonding process. Emission characteristics obtained for two- and three-electrode configurations have been reported. The influence of the encapsulation conditions on emission degradation in time has been investigated.

MEMS ion-sorption high vacuum pump

In the article a miniature MEMS-type ion-sorption vacuum pump has been presented. The influence of electric and magnetic field, as well as horizontal and vertical dimensions of the micropump and type of material used for electrodes on the pump properties has been investigated. It has been found that the micropump works efficiently as long as the magnetic field is higher than 0.3 T, and pumping cell is larger than 1x1x1 mm3. The pump allows generating vacuum at the level of 10-7-10-9 hPa in 100 mm3 volume.

A concept of fully integrated MEMS-type electron microscope

In this article a concept of the fully, on-a-chip, integrated MEMS electron microscope and high vacuum MEMS micropump is discussed. The device is formed as a multilayer sandwich of anodically bonded glass/silicon part. The “active” part contains field emitting CNT electron source with proper configuration of electrodes forming an electron beam. Electron beam hits a thin membrane, passes through sample, and generates signal on a detector placed outside a high vacuum region.

Preliminary characterization of the ion-sorption micropump

The microengineered miniature silicon-glass micropump has been shown for the first time ever. The device consists of lateral CNT-based cold cathode surrounded by an oval anode. Field-emitted electrons ionize residual gas particles, which are collected by a collecting electrode covered with active thin-film Ti getter co-operating with NEG getter (SAES, Italy). Preliminary results showed good pumping (~10-4 hPa), about two orders of magnitude better then NEG getter can achieve.

Improved ionization efficiency in MEMS-type ion-sorption micropump

In this paper we demonstrate how to increase ionization efficiency inside a MEMS-type ion-sorption micropump, and therefore have a possibility to obtain very high vacuum inside miniature nanoelectronics devices. Three different approaches were utilized to achieve this goal - electrodes of the micropump were covered with (or made of) nanomaterials having either good field emission properties (carbon nanotubes) or high secondary emission coefficient (magnesium oxide nanopowder and porous silicon). For all of the modified electrodes a significant improvement was observed, in the case of MgO discharge current increased more than 1000 times.

Integration of a MEMS-type vacuum pump with a MEMS-type Pirani pressure gauge

This paper describes the use of a miniature Pirani pressure sensor to measure the properties of a miniature vacuum pump. The construction and fabrication process of the integrated device is presented. Results of characterization of both MEMS devices performed separately in reference vacuum system and after their integration are shown.

Vertical MEMS-type field-emission electron source

The paper describes a MEMS-type field emission electron source fabricated as a multilayer silicon-glass structure, which can be a part of other miniature vacuum devices. Here, emission properties obtained in 2-and 3-electrode configuration have been reported.

High vacuum micropump for miniature nanoelectronics devices

The microengineered 5×5×3.2 mm3 silicon-glass glow-discharge high vacuum micropump has been presented in this article. Preliminary results showed very good pumping properties (p <; 10-6 hPa), more than three orders of magnitude better than NEG getter can provide. Micropump integrated with other nanoelectronics devices helps to stabilize their operation.