Thin-film transistor used as heating element for microreaction chamber
AssigneeSTMicroelectronics S.r.l.
InventorFrank R. Bryant
Life of this patent
Estimating the term…
Abstract
The thin film transistor formed of polycrystalline silicon is positioned adjacent a heat reaction chamber. The gate electrode for the transistor is formed within a silicon substrate and a gate dielectric is positioned over the gate electrode. A pass transistor is coupled to the gate electrode, the pass transistor having a source/drain region in the same semiconductor substrate and positioned adjacent to the gate electrode of the thin film heating transistor. When the pass transistor is enabled, a voltage is applied to the gate electrode which causes the current to flow from the drain to the source of the thin film transistor. The current flow passes through a highly resistive region which generates heat that is transmitted to the heat reaction chamber.
Claims7
A method of making a semiconductor heater assembly, comprising:
- forming electrically insulating regions within a semiconductor substrate;
- forming a gate electrode within the semiconductor substrate;
- forming a gate dielectric over the gate electrode and located between the insulating regions;
- forming a layer of polycrystalline silicon overlying the insulating regions and the insulating layer;
- doping source and drain regions within the polycrystalline silicon layer to have a selected low resistivity to obtain a thin-film transistor;
- forming a heat responsive reaction chamber over the resistive region.
A method, comprising:
- Introducing a fluid into a microreaction chamber formed on a semiconductor substrate;
- Heating the fluid in the chamber to a selected temperature, the heating step being performed by passing a current through a resistive channel region between a source and drain of a transistor formed adjacent to the chamber, and causing, thereby, the channel region to increase in temperature and to heat the fluid in the adjacent chamber by conduction;
- and
- Regulating the degree of heat produced in the channel region by adjusting a voltage level on a gate terminal of the transistor.
Dependencies are inferred from the claim text.