Honeywell G.m.b.h.

Honeywell International Inc.

James O Holmen

Robert G Johnson

Jeffrey Alan Ridley

Barrett E Cole

Robert E Higashi

Steven D James

David K Greenlaw

G Benjamin Hocker

Ronald B Foster

Uppili Sridhar

Steven R Weeres

An RTD having a thin film HfN resistor formed on a substrate for temperature detection in accordance with the resistance of the HfN resistor. The RTD is a two lead device having high accuracy and a wide temperature range from 20 to 1400 degrees Kelvin. The substrate has bonding pads or contact strips connected to the resistor and processing electronics. An SiN thin film passivation layer is formed on the resistor and substrate. Two leads connect the bonding pads or contact strips to processing electronics and an indicator.

Wide temperature range RTD

A structure and method of making resistive emitting members which exhibit high resistivity while at the same time providing high temperature operation significantly above that known in the art. Specifically the use of nitrides of Group IVB transition metals from the periodic table, exclusive of titanium is described.

High temperature ZrN and HfN IR scene projector pixels

A thermal isolation microstructure fabricated by a process which allows the ultra thinning of support legs for the microdetector.

Thermal isolation microstructure

A two-level IR detector imaging array of high fill-factor design. The upper microbridge detector level is spaced above and overlies the integrated circuit and bus lines on the substrate surface below.

Thermal sensor

The marginal adhesion of platinum to silicon nitride is a serious issue in the fabrication of microbridge mass air flow sensors. High temperature stabilization anneals (500.degree.-1000.degree. C.) are necessary to develop the properties and stability necessary for effective device operation. However, the annealing process results in a significant reduction in the already poor platinum/silicon nitride adhesion. Annealing at relatively high temperatures leads to the development of numerous structural defects and the production of non-uniform and variable sensor resistance values. The use of a thin metal oxide adhesion Layvr, approximately 20 To 100 angstromw in thickness is very effective in maintaining platinum adhesion to silicon nitride, and through the high temperature anneal sequence.

Adhesion layer for platinum based sensors

A microbridge air flow sensor which has a sealed etched cavity beneath the silicon nitride diaphragm so that the cavity is not susceptible to contamination from residual films or other material accumulating within the cavity. The cavity thermally isolates the heater and detectors which are encapsulated in the diaphragm. The cavity is fabricated by front side etching of the silicon wafer. Narrow slots are made through the silicon nitride diaphragm to expose a thin film (400 angstrom) rectangle of aluminum. A first etch removes the aluminum leaving a 400 angstrom very shallow cavity under the diaphragm. Anisotropic etch is then introduced into the shallow cavity to etch the silicon pit.

Thin film orthogonal microsensor for air flow and method

Method for making thin film orthogonal microsensor for air flow

An improved connector pad stack structure for use in microstructure devices having a silicon nitride surface in which the sensor metal such as platinum or Ni-Fe is eliminated from the pad bonding site and only adhesion promoting metals are used on the Si.sub.3 N.sub.4 to provide a stronger, more durable and reliable pad stack.

Microbridge sensor bonding pad design for improved adhesion

A microbridge air flow sensor having a silicon nitride diaphragm formed on the surface of a single crystal silicon wafer. A rectangular 500 angstrom thick sacrificial layer was deposited on the silicon surface before the silicon nitride to define the exact position of the diaphragm. A series of etches from the backside of the wafer is performed to fabricate the device. A first silicon anisotropic etch from the backside is stopped at the sacrificial layer. A sacrificial layer selective etch is applied from the backside first pit to the sacrificial layer to remove all of the rectangular sacrificial layer. Anisotropic etch is again applied into the space created by the removed sacrificial layer whereby the second etch attacks the silicon exposed by the removal of the sacrificial layer and etches downward forming a second anisotropic etch pit. Thus all the etches are from the backside of the silicon wafer.

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Minnetonka, MN, United States of America

James O Holmen