A device for measuring the volume of objects by use of air pressure includes a container which has a primary rod and a secondary rod, desired portions of which can be controllably disposed in the interior of the container. These rods are graduated so that it is possible to note the degree of penetration of the primary rod into the container and, similarly, the volume of the portion of the second rod in the container. The container is designed to be closed airtight and to hold the object of unknown volume. The primary rod is forced into the container to generate an elevated pressure which pressure is noted. Thereafter, the object is removed and in its place a sufficient portion of a second rod, estimated to equal the volume of the object being measured, is disposed in the container. The primary rod is then repositioned as before with the idea of obtaining the same pressure reading as before. If the same pressure reading is not obtained, the amount of penetration of the secondary rod into the container is readjusted and the primary rod is again inserted to the same degree to obtain the originally noted pressure reading. These steps are repeated until a close enough pressure reading is obtained at which point the volume of the object being measured is determined by noting the degree of penetration of the secondary rod.
An entrapped gas measuring apparatus includes a reservoir housing with a reservoir which is adapted to receive a material sample and to expand according to an expansion of the material sample when a negative pressure is applied externally to the reservoir. A parameter indicating the change in volume of the reservoir during the expansion, such as the actual change of volume of the reservoir or a change in position of a moveable wall which at least in part defines the reservoir, is detected by a detector. A processor coupled to the detector is used to determine the amount of entrapped gas based upon the detected parameter. The amount of entrapped gas determined by the processor may be the percent volume of the entrapped gas in relation to the overall volume of the sample, or may be the actual volume of the entrapped gas in the sample. Based at least in-part upon the measured amount of entrapped gas within the sample, the processor is further adapted to determine at least one of: percent volume of the substrate in the sample in relation to the overall volume of the sample; actual volume of the substrate in the sample; or density of the sample or substrate within the sample. The entrapped gas measuring apparatus may be used to produce a material having a known amount of entrapped gas by: making a first material according to a first method and which has a first amount of entrapped gas; applying a negative pressure to the sample such that the sample expands from a first volume to a second volume; detecting a parameter which is indicative of the change of sample volume under the applied negative pressure; comparing the detected parameter with a predetermined range for the parameter; and, if the detected parameter is not within the predetermined range, making a second material according to a second method which has a second amount of entrapped gas that is within the predetermined range.
The invention comprises a method for fabricating a monolithic chip containing integrated circuitry as well as a suspended polysilicon microstructure. The inventive method comprises 67 processes which are further broken down into approximately 330 steps. The processes and their arrangement allow for compatible fabrication of transistor circuitry and the suspended polysilicon microstructure on the same chip.
