Student: Tho T. SnowAdvisor: Prof. Mustafa G. Guvench

1
Design, Fabrication, and Testing a Four- Quadrant
Silicon Photosensor
Student Tho T. Snow Advisor Prof. Mustafa G.
Guvench Electrical Engineering Department -
University of Southern Maine
A four-quadrant Si photosensor is designed to
fabricate on a 4-in n-type wafer manufactured by
Fairchild Semiconductor
The goal of this project is to design and
fabricate a Si photosensor consisting of four
identical photodiodes placing in a square pattern
on a Si chip. The photosensor will be used to
sense the 2- dimension position of the chip with
respect to the spot defined by Red 632.8 nm He-Ne
laser beam.
Our Goal
This is the Curve Tracer used in the I-V curve
plotting and testing of the photodiode.
The oxide thickness and the doping concentration
of the Si layer underneath the oxide can be
determined using capacitance versus bias voltage
measurements as shown. And the deposited metal
thickness can be determined using the four point
resistance probe test