A Conductivity Modulated Polysilicon Thin-Film Transistor
This paper reports a novel high voltage Conductivity Modulated Thin-Film Transistor (CMTFT) fabricated using polycrystalline silicon. The transistor uses the idea of conductivity modulation in the offset region to obtain a significant reduction in on-state resistance. Experimental on-state and off-state current-voltage characteristics of the CMTFT have been compared with those of the conventional offset drain device. Results show that the CMTFT has six times to more than three orders of magnitude higher on-state current handling capability for operating at drain voltages ranging from 15 V to 5 V while still maintaining low leakage current and providing even faster switching speed. The CMTFT devices can be fabricated using a low temperature process (620/spl deg/C) which is highly desirable for large area electronic applications.<<ETX>>
A p-channel poly-Si/Si/sub 1-x/Ge/sub x//Si sandwiched conductivity modulated thin-film transistor
A p-channel poly-Si/Si/sub 1-x/Ge/sub x//Si sandwiched conductivity modulated thin-film transistor (CMTFT) is proposed and demonstrated in this paper for the first time. This structure uses a poly-Si/Si/sub 1-x/Ge/sub x//Si sandwiched structure as the active layer to avoid the poor interface between the gate oxide and the poly-Si/sub 1-x/Ge/sub x/ material. Also an offset region placed between the channel and the drain is used to reduce the leakage current. Furthermore, the concept of conductivity modulation in the offset region is used to provide high on-state current. Results show that this structure provides high on-state current as well as low leakage current as compared to that of conventional offset drain TFTs. The on-state current of the structure is 1.3-3 orders of magnitude higher than that of a conventional offset drain TFT at a gate voltage of -24 V and drain voltage ranging from -15 to -5 V while maintaining comparable leakage current.
Ocean thermal energy conversion: The promise of a clean future
Due to the world's heavy dependence on fossil fuels for electricity, pollution and global warming is on the rise. However, numerous countries are still relying on diesel generators as their main source of energy. There is a lack of practical alternative energy source that can meet the global energy demand without posing any threat to the natural environment. Ocean Thermal Energy Conversion (OTEC) is a concept that has the potential to address this growing issue. It is basically a mechanism that exploits the temperature difference between warm surface seawater and cold deep ocean water, to produce electricity. Although OTEC has a low energy density, the thermal energy in the ocean is vastly abundant. OTEC development has been dormant for a long time since it was first proposed in 1881. However, it has now regained recognition worldwide as a realistic solution to our world energy issue. Instead of having a great potential for power generation, it also carries the ability to produce high value products from the large volume of Deep Sea Water (DSW) that can be released as byproducts of OTEC plant operation. These products can hold a very profitable place in industries such as pharmaceutical, food, cosmetics and mineral water production. Further research on ocean current and DSW properties can someday lead to the commercial used of OTEC. This paper is a review of the basic concept, present status and future prospects of OTEC around the world.