Monolithic III-nitride based LED micro-arrays offer many potential applications due to their superior characteristics such as high brightness, long lifetime and high contrast. In previously developed passive addressable LED micro-arrays, display dimensions and pixel brightness were limited by the loading effect in the same row or column. Therefore, a new addressing scheme and fabrication technology are needed to improve the operation effectiveness of the LED micro-arrays.

In this thesis, III-nitride based light emitting diodes on silicon (LEDoS) displays were designed and fabricated by integrating LED micro-arrays and active matrix substrates through Flip-Chip technology. An active matrix driving scheme was designed to provide sufficient drive capability and individual contro...[ Read more ]

Monolithic III-nitride based LED micro-arrays offer many potential applications due to their superior characteristics such as high brightness, long lifetime and high contrast. In previously developed passive addressable LED micro-arrays, display dimensions and pixel brightness were limited by the loading effect in the same row or column. Therefore, a new addressing scheme and fabrication technology are needed to improve the operation effectiveness of the LED micro-arrays.

In this thesis, III-nitride based light emitting diodes on silicon (LEDoS) displays were designed and fabricated by integrating LED micro-arrays and active matrix substrates through Flip-Chip technology. An active matrix driving scheme was designed to provide sufficient drive capability and individual controllability of each LED pixel. Three generations of the LEDoS displays were introduced and demonstrated.

Firstly, an 8×8 monolithic LEDoS display was fabricated with an emission wavelength of 440nm. The pixel size was 300μm by 300μm in a square shape with a 350μm pitch. The LEDoS display panel was measured by applying scan and data signals, demonstrating sufficient driving capability for the LED micro-array. Secondly, an 8×8 LED micro-array unit was designed as a basic module. With this module, the LEDoS display panel can be scaled up to 16×16, 24×24 or even bigger according to full-custom designs of the active matrix substrates. Forward voltage uniformity of the LED pixels was greatly improved using a novel double-ground structure. Red, green and blue phosphors were applied on the top of the LEDoS panel to realize a full-color display. Thirdly, high-resolution and fine-pixel LED micro-arrays were designed with either 30×30 or 60×60 pixels on a single chip. The circular shape pixels had diameter of diameter of 100μm in 140μm pitch and 50μm in 70μm pitch, respectively. With a peripheral driving board, the LEDoS micro-display panel was programmed row by row and column by column individually. Representative images, numeric and alphabets were displayed. The LEDoS has potential applications such as micro-displays, portable projectors, bio-sensor arrays, back-light units for LCDs and programmable lighting sources.