公开(公告)号：WO0195391A8

公开(公告)日：2002-03-28

申请号：PCT/US0117927

申请日：2001-06-01

Applicant: INFINEON TECHNOLOGIES CORP ,  IBM

Inventor： NESBIT LARRY ,  MCSTAY IRENE LENNOX ,  RADENS CARL ,  TEWS HELMUT HORST ,  DIVAKARUNI RAMA ,  MANDELMAN JACK

IPC: H01L21/8242

CPC classification number: H01L27/10861 ,  H01L27/10867

Abstract: A method of forming relatively thin uniform insulating collar in the storage trench of a storage trench DRAM cell. A DRAM trench is first formed in a silicon substrate. Then, a nitride liner (81) is deposited on the silicon trench walls. The nitride liner may be deposited directly on the silicon walls or on an underlying oxide layer (79). A layer of amorphous silicon (83) is then deposited over the nitride liner. A silicon nitride layer is deposited on the oxidized surface of the amorphous silicon. A resist (83) is formed in the lower portion of the trench, and the exposed silicon nitride layer on top of the amorphous silicon is removed, leaving the upper portion of the amorphous silicon layer exposed. The upper portion of the layer of amorphous silicon is then oxidized so as to form a relatively thin, uniform collar (89) along the entire circumference of the trench. The nitride liner underlying the amorphous silicon layer enhances the thickness uniformity of the amorphous silicon layer and thereby the uniformity of the resulting oxide collar. The nitride liner also acts to limit lateral oxidation of the silicon trench walls during oxidation of the amorphous silicon layer. The nitride liner underlying the collar is also effective in cell operation to control the cell charge at the collar-substrate interface.

Abstract translation: 一种在存储沟槽DRAM单元的存储沟槽中形成相对薄的均匀绝缘环的方法。 首先在硅衬底中形成DRAM沟槽。 然后，氮化物衬垫（81）沉积在硅沟槽壁上。 氮化物衬垫可以直接沉积在硅壁上或下面的氧化物层（79）上。 然后在氮化物衬垫上沉积一层非晶硅（83）。 在非晶硅的氧化表面上沉积氮化硅层。 在沟槽的下部形成抗蚀剂（83），去除非晶硅顶部的露出的氮化硅层，使非晶硅层的上部露出。 然后，非晶硅层的上部被氧化，以便沿沟槽的整个圆周形成相对较薄的均匀的环（89）。 非晶硅层下面的氮化物衬垫增强了非晶硅层的厚度均匀性，从而提高了所得氧化物环的均匀性。 氮化物衬垫还用于在非晶硅层的氧化期间限制硅沟槽壁的横向氧化。 在套环下面的氮化物衬垫在电池操作中也有效地控制在衬套 - 衬底界面处的电池电荷。

公开(公告)号：DE10261330A1

公开(公告)日：2003-08-14

申请号：DE10261330

申请日：2002-12-27

Applicant: INFINEON TECHNOLOGIES CORP

Inventor： TEWS HELMUT HORST ,  KUDELKA STEPHAN P ,  SCHROEDER UWE ,  MCSTAY IRENE LENNOX ,  RAHN STEPHEN

IPC: H01L21/02 ,  H01L21/033 ,  H01L21/308 ,  H01L21/311 ,  H01L21/3213 ,  H01L21/8242

Abstract: In a process for making a DT DRAM structure, the improvement of providing a surface area enhanced DT below the collar region and node capacitance that does not shrink with decreasing groundrule/cell size, comprising:a) providing a semiconductor substrate having a collar region and an adjacent region below the collar region, the collar region having SiO deposited thereon;b) depositing a SiN liner on said collar region and on the region below the collar;c) depositing a layer of a-Si on the SiN liner to form a micromask;d) subjecting the structure from step c) to an anneal/oxidation step under a wet environment at a sufficient temperature to form a plurality of oxide dot hardmasks;e) subjecting the SiN liner to an etch selective to SiO;f) subjecting the structure from step e) to a Si transfer etch using a chemical dry etch (CDE) selective to SiO to create rough Si surface;g) stripping SiO and the SiN; and forming a node and collar deposition.