LOW STRESS, ULTRA-THIN, UNIFORM MEMBRANE, METHODS OF FABRICATING SAME AND INCORPORATION INTO DETECTION DEVICES

摘要

The present disclosure is directed, in part, to a method for fabricating a low-stress, ultra-thin membrane as well as the low-stress, ultra-thin membrane formed by this method. The method includes: layering a first layer on a semiconductor substrate; etching a hole in the first layer; layering a second layer on the membrane of the first layer and over the hole; and etching the substrate beginning from the bottom surface thereof, such that at least a portion of the substrate aligned with the hole in the first layer is removed. The first and second layers are made of substantially the same material, which will usually be silicon nitride, however, it is contemplated that other dielectric materials could be used, but it is preferred that the second layer has an amorphous structure. It is preferred that the second layer be formed with a slightly bubble-shape to help deflect stresses on the second layer. Generally, low pressure chemical vapor deposition will be used to create at least the first and second layers. As a result of this basic method, the second layer has an ultra-thin thickness. Among other devices, the ultra-thin membrane is useful in a device for detecting physical characteristics of a sample bombarded with electrons. In such a device, the ultra-thin, low-stress membrane is positioned adjacent a electron detector. The device may further include an evacuated chamber at least partially bounded by the ultra-thin low-stress membrane.