Method of manufacturing a semiconductor device
Disclosed is a method of manufacturing a semiconductor device. In ion implantation process for controlling the threshold voltage of the transistor or the semiconductor device such as a flash memory cell, the dose of the impurity capable of securing the uniformity is implanted by minimum. The retained dose of the impurity is controlled by out gassing the implanted impurity by means of a cleaning process. Therefore, a uniform distribution characteristic of the implanted impurity could be obtained. A transistor or a flash memory cell of a low operating voltage could be manufactured.
1. A method of manufacturing a semiconductor device, comprising the steps of:
providing a semiconductor substrate on which a given process is implemented in order to form a semiconductor device;
forming an ion implantation layer in a well by means of an ion implantation process; and
controlling the impurity concentration of the ion implantation layer by means of a cleaning process, wherein the cleaning process is implemented using a solution of fluoric acid series and a SC-1(NH 4 OH/H 2 O/H 2 O) solution to remove a native oxide film on the surface of the semiconductor substrate.
2. The method as claimed in claim 1 , wherein the solution of a fluoric acid series employs diluted HF in which H 2 O:HF is mixed in the ratio of 1:1˜50:1 as an undiluted solution.
3. The method as claimed in claim 1 , wherein the cleaning process controls the concentration of the remaining impurity by controlling the concentration of the solution or the progress time.
4. The method as claimed in claim 1 , wherein the ion implantation layer is formed by implanting an impurity of 1E11˜1E13 ion/cm 2 with an energy of 5˜50 keV.
5. The method as claimed in claim 4 , wherein the impurity is boron.
6. The method as claimed in claim 4 , wherein the impurity is implanted at an angle of 3˜13°.
7. A method of manufacturing a semiconductor device, comprising:
providing a semiconductor substrate on which a given process is implemented in order to form a semiconductor device;
forming an ion implantation layer by means of an ion implantation process; and
controlling the impurity concentration of the ion implantation layer by means of a cleaning process, wherein the cleaning process is implemented using a solution of fluoric acid series and a SC-1(NH 4 OH/H 2 O/H 2 O) solution to remove a native oxide film on the surface of the semiconductor substrate;
sequentially forming a tunnel oxide film and a first polysilicon layer over a semiconductor substrate and then implementing patterning;
forming an isolation film in an isolation region of the semiconductor substrate;
sequentially forming a dielectric film, a second polysilicon layer and a silicide layer on the entire structure of the semiconductor substrate;
sequentially patterning the silicide layer, the second polysilicon layer and the dielectric film by means of an etch process using a control gate mask;
patterning the first polysilicon layer by means of a self-aligned etch process; and
forming source/drain in the semiconductor substrate around the first polysilicon layer.
8. The method as claimed in claim 7 , wherein the source/drain has a DDD junction structure.