1. Field of the Invention
The present invention relates generally to photodetectors, particularly photodetectors used in accelerometers, and methods for forming such photodetectors.
2. Description of Related Art
In some accelerometers, a light source such as an light emitting diode (LED) is used in conjunction with a moveable shadow arm to project light onto a pair of photodiodes. Movement of the shadow arm caused by changes in acceleration experienced by the accelerometer results in changes in how light from the LED projects onto the photodiodes, and correspondingly affects current flow through the photodiodes. In such accelerometers, the photodiodes are often subject to and/or the source of a number of problems. Such problems include, but are not necessarily limited to, excessive amounts of dark current (current arising from thermal energy rather than light), bias shifts resulting from minor shifts in light distribution, conductors blocking light, conductors increasing the distance between the shadow arm and photodiodes, and increased sensitivity of the accelerometer to temperature changes. As such, there is a need for improved photodiodes and methods of forming such diodes, particularly as they incorporated into accelerometers.