Chinese Academy of Sciences

Zuoya Yang

Bo Tong Liu

Chao B Zhang

Ting Ting Zhang

Zhitang Song

Guanping Wu

Xudong Wan

Zhifeng Xie

An epitaxial growth method for preventing auto-doping effect is presented. This method starts with the removal of impurities from the semiconductor substrate and the reaction chamber to be used. Then the semiconductor substrate is loaded in the cleaned reaction chamber to be pre-baked under vacuum conditions before the extraction of the dopant atoms desorbed from the surface of the semiconductor substrate. Next, under high temperature and low gas flow conditions, a first intrinsic epitaxial layer is formed on the surface of said semiconductor substrate. Following this, under low temperature and high gas flow conditions, a second epitaxial layer of required thickness is formed on the structural surface of the grown intrinsic epitaxial layer. Last, silicon wafer is unloaded after cooling. This method can prevent auto-doping effect during the epitaxial growth on semiconductor substrate and thus ensure the performance and enhance the reliability of the devices in peripheral circuit region.

Method of preventing auto-doping during epitaxial layer growth by cleaning the reaction chamber with hydrogen chloride

The present invention discloses a method of fabricating dual trench isolated epitaxial diode array. This method starts with the formation of heavily-doped first conductivity type regions and heavily-doped second conductivity type regions on the substrate, followed by epitaxial growth, then the formation of the isolations between diode array word lines by deep trench etch and the formation of the isolations between bit lines vertical to deep trenches by shallow trench etch, and finally the formation of separate diode array cells in the regions enclosed by deep and shallow trench isolations by ion implantation. This invention also provides a method of preventing the crosstalk current between adjacent word lines and bit lines of epitaxial diode arrays isolated by foregoing dual shallow trenches. This invention can be used for diode-driven, high-density, large-capacity memory, such as phase change random access memory, resistive memory, magnetic memory and ferroelectric memory; the method thereof is completely compatible with conventional complementary metal-oxide semiconductor (CMOS) process, and because the diode arrays can be formed before the formation of peripheral circuits, no drift of peripheral circuits will be caused by the thermal process thereof, thereby solving the technical challenge of fabricating high-density, large-capacity embedded phase change random access memory.

Method of fabricating dual trench isolated epitaxial diode array

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Shanghai, China

Zuoya Yang